Use the first trip through Undusted: Letters from the Past as a restricted-tool run. Take every object to a real 100%, clean only with the sponge and toothbrush whenever those tools are available, and leave the cloth and air blow gun untouched until the Level 17 audit confirms every required mark and Simple and Clean is present. That order carries one continuous route through the story, the full-clean milestones, and nearly every object-specific achievement before two short replays.
The last object sits beyond the credits, so Level 16 is not the end of a safe 100% route. Watch the ending, return to level select, and clean the Level 17 pendant before auditing Every Last Speck, Simple and Clean, and the two level-select marks. Written routes disagree about the exact level where the two completion achievements pop; the observable all-17 state is the reliable finish line.
Scope and patch boundary: this route covers the released Windows game on Steam, app 2891020, and its 36 Steam achievements. It was checked on August 7, 2026 against the official Steam listing and the developer’s v1.0.2 achievement patch note dated October 20, 2025. That patch added a stage-select mark for sponge-and-toothbrush clears, lengthened the listen required for Dad’s Final Song, clarified that Patience is an Art needs 100%, and moved the corrected Squeak! trigger to the snow-globe stage. No later public gameplay patch note appears in the official feed through the check date.
Spoilers: level names, objects, the telephone number, the post-credits stage, and achievement triggers appear below. The story itself is not retold.
Two level-select marks govern the entire route
A stage can be wrapped at 99%, but that is only story progress. The completion achievements use the 100% state shown on level select. After v1.0.2, an additional mark shows whether an eligible object reached 100% using only the sponge and toothbrush. Check both marks after every level; a missing tool mark is a precise replay target, while a missing 100% mark means dirt remains somewhere on that object.
For the baseline run, let only the sponge or toothbrush remove dirt. Level 6 is the known exception because the plush object supplies only its small vacuum; still clean it to 100%, but do not expect the restricted-tool mark there. Buttons, hinges, cranks, keys, dials, and shaking motions are object interactions rather than alternate cleaning tools. The verified routes perform those actions during the baseline pass without abandoning Simple and Clean.
- Levels 1–17: reach 100% everywhere. Use only the sponge and toothbrush when offered; use the forced vacuum in Level 6. Do the secret object interactions on this pass, then inspect both level-select marks before spending a held-back tool.
- Level 7 replay: touch the snow globe with the cloth once for Squeak!.
- Level 11 air-only replay: restart the music box dirty and let the air blow gun do all cleaning until the counter reaches 100%. Its first use also awards Air it Out!.
Hints need a separate plan. Keep Tab completely untouched in Level 2 for No Help Needed. In Level 3, try Tab three times before the game announces that hints are available to earn It’s Still Not Working!. Once those two tests are finished, use hints freely when a moving part or opposite face is hiding the final fraction.
Objects 1–6: bank the input achievements while tools are simple
Level 1 — Memories Beneath the Dust
The Chapter 0 tutorial is numbered Level 1 in the achievement list. The front-door key supplies only a toothbrush. Zoom close, rotate the key through both faces and every edge, and keep working after the Wrap Up prompt appears. Hints are introduced here, but a tutorial clear cannot satisfy No Help Needed. Reaching the level’s finish awards A Dusted Key.
Level 2 — A Special Photo
The picture frame is the cleanest no-hint test because it is flat and supplies only the sponge. Sweep both faces, then slow down at the four front grooves and the outer rim. Do not press Tab at any point. Watch the percentage while revisiting each corner; if it still rises, the level is not ready to finish. A 100% no-hint clear gives Bunny Ears! and No Help Needed.
Level 3 — A Fitting Appearance
Before cleaning enough to unlock hints, press Tab three times for It’s Still Not Working!. Then use the sponge on the broad porcelain and switch to the toothbrush for the repaired cracks, cup interior, broken handle edge, foot, and the mark underneath. The failure signal is a clean-looking exterior with the counter still moving when the brush crosses the inner wall or base. Finishing the teacup awards Shattered.
Level 4 — What Glows in the Dark
Begin on the ink bottle’s large faces with the sponge, then trace the toothbrush around both label borders, the neck, stopper, and the channels on the underside. Rotate far enough to see the bottom rather than brushing its silhouette from the side. Shining in the Darkness comes with the level clear. If Levels 1–4 all show 100%, A Shining Start should arrive here as the four-object milestone.
Level 5 — Achieving Happiness
Expose all seven playable holes on the turtle-shaped ocarina before attempting the melody. Keep the head pointing upward so left and right do not reverse when the object turns. Use the toothbrush to sound this sequence:
- Shell facing you: upper-left, upper-right, lower-left, lower-right.
- Belly facing you, head still up: lower-left, lower-right, then the upper hole.
The opening at the mouth is not part of the seven-note order. Let each hole produce its note before moving on. The level awards A Little Ditty; the ordered scale awards Clean as an Ocarina. If the scale does not register, finish no more dirt, restart the stage, restore the same orientation, and repeat the seven inputs rather than guessing a different melody.
Level 6 — A Discreet Apology
This plush object deliberately replaces the normal tools with a small vacuum. Work around both ears, underneath the body, and around the tail attachment before accepting 100%. No Means No arrives with the clear. The stage still matters to Every Last Speck, but it is excluded from the sponge-and-toothbrush requirement because neither tool is available.
Objects 7–12: open every mechanism before chasing dirt
Level 7 — Unforgettable Moments
Do not clean with the cloth yet. The toothbrush can polish the globe’s glass slowly enough to preserve the restricted-tool mark; use the sponge and brush on the base and decorations. Removing one attached flower awards Too Pretty to Clean. Grip the globe as if rotating it and swing it back and forth until the snow falls inside for Let It Snow. The story clear is Snow-capped. Save the cloth’s Squeak! trigger for a replay after Level 17.
Level 8 — Frozen Time
Put down the cleaning tool and activate the release on the pocket watch’s top edge. The case opens, exposes another dirty face, and awards With These Hands. Keep the cloth unused: brush the inner glass, patterned cover, top button, and hanging loop from several angles. A closed watch with a stalled percentage means the hidden face has not been checked. The stage clear awards Left Behind. Because this is the eighth object, it is the natural checkpoint for Nearly Spotless; if that milestone is absent, inspect the earlier 100% stamps before moving on.
Level 9 — What I Found in the Darkness
Clean enough of the MIDI controller to identify its controls, then switch on the top power button. Move the volume slider so the toothbrush can reach its channel, and toggle the power switch to expose both sides of its recess. The rear screw holes also hold small patches.
For Echo… Echo… Echo…, first use the newer community-tested setting: left knob pointing right, right knob pointing left, then press the upper-left white pad. Older written routes say both knobs should point left. If the first configuration produces a sound but no unlock, change only the left knob to the older position and press the same pad again. This conflict is why one fixed setting should not be treated as permanent. Clearing the controller awards In Darkness Found.
Level 10 — A Melody of Comfort
The cassette player hides dirt through button travel. Press each top button down and brush the newly exposed sides of its neighbors. Use the far-right control to open the tape bay, then rotate the object to reach the bay walls, underside of the lid, and the clip on the back. If hints keep pointing toward the top, cycle the buttons instead of scrubbing their visible caps. Words Gone Astray marks the clear.
Level 11 — The Right to Hurt
Ignore the air blow gun on the baseline pass. Release the front latch and open the music box, then turn the side crank so the internal roller moves beneath the brush. Inspect the key itself, the box’s inner walls, the throat and rim of the horn, and the narrow neck joining the horn to the mechanism. A stationary roller can conceal an apparently unreachable dirty strip.
Keep the mechanism playing after winding it. Official v1.0.2 notes say Dad’s Final Song now requires a longer listen, so a brief note is not a reliable success signal. Wait for the Steam unlock before leaving the melody. Completing the object awards Shouldn’t Have Said That.
Level 12 — A Radiant Dream
Open the front lens cover, press the lightning-symbol button on the back to power the camera and raise its flash, extend the lens, and press the top shutter. Doing the full sequence removes any ambiguity over the lens position and awards Say Cheese!.
For 100%, move the lens in and out while brushing its base, inspect the front panel behind the open cover, and clean around the raised flash from both sides. Do not use the air gun on this pass. What Was Left Inside arrives with the level clear.
Objects 13–17: finish the story, then clean the pendant
Level 13 — Where That Dream Now Resides
Although the trophy has no hidden compartment, its glass top creates a false depth cue: a highlighted patch may sit on the far face rather than the surface under the cursor. Rotate the glass through a full turn, brush its rim and underside, then check the joint above the base. The stage awards What Had Always Been There. If Nearly Spotless was missing at Level 8, inspect level-select percentages rather than cleaning the trophy repeatedly.
Level 14 — Our Last Moment
Before selecting a tool, press any typewriter key five times for Like She Once Did. Continue typing to drive the carriage across its rail, clean the section it vacates, then use the lever on the left to return it and uncover the opposite section. Brush between the keys and around the two small controls above the keyboard. A carriage left in one position is the usual reason the final dirt cannot be seen. Unexceptional is the story clear.
Level 15 — Words Left Unsaid
Flip the receiver so the dial tone is active. Enter 2-1-7 on the rotary dial: for each digit, drag clockwise until the dial reaches the metal stop, release it, and wait for the ring to return completely before starting the next digit. A correct digit produces a beep. After the 7 returns, wait for the recorded message and the An Excuse to Call You unlock.
If the call stays silent, do not spin the three digits faster. Replace the receiver, press the small white reset button at the lower right, lift or flip the receiver again, and repeat. Make sure the pointer actually travels over the selected number and reaches the stop. No later official phone-trigger fix was found, so the beep and message are the checkpoints—not merely seeing the dial move.
For cleaning, repeatedly dial 7 to hold the ring open long enough to brush beneath the numbers. Flip the receiver to expose its underside and press the small front buttons to reach their adjacent walls. Finishing this object awards If I Had Called First….
Level 16 — A Letter from the Past
This ornate key supplies only the toothbrush. Turn it edge-on and clean the inner walls of every opening in the handle; a face-on view cannot reach those narrow surfaces. Take the key to 100%, watch the ending, and let the credits finish. The level awards Nothing Left Undusted, while the story ending awards Letters From the Past.
The credits are not the final completion check. Sources conflict on whether Every Last Speck appears here or after the hidden object, so do not spend time trying to force a popup on Level 16. Confirm the first sixteen 100% marks, continue to the pendant, and audit the achievement only after the seventeenth object is clean.
Level 17 — The Pendant
Return to level select after the credits and open the new pendant stage. Open the pendant before cleaning its inside, then use its sponge and toothbrush on the inset glass, hinge, inner rim, back, and outer edge until the object shows 100% and the restricted-tool state.
Finishing the hidden object awards Etched in Heart. Now audit the level-select screen instead of trusting one popup: every object must show 100%, and every eligible stage must retain the sponge-and-toothbrush mark. If Every Last Speck or Simple and Clean is still absent, the missing icon identifies the replay more reliably than any single promised unlock level.
Spend the held-back cloth and air gun
Only start this cleanup after Simple and Clean has appeared. Replay Level 7, wipe any dirty area of the snow globe with the cloth, and wait for Squeak!. There is no reason to take that replay to 100% unless its ordinary completion mark was also missing.
For the air achievements, Level 11 is the clearest written route. Restart the music-box stage from a dirty state and let only the air blow gun remove dirt. The first contact awards Air it Out!; reaching 100% without another cleaning tool awards Patience is an Art. The gun’s gauge rises toward red as it heats. Release the trigger and wait for it to return toward green instead of dragging an overheated tool over the same surface.
On a successful final replay, Air it Out! appears after the first burst and Patience is an Art waits for the object to reach 100%. If the first appears but the second does not, a mixed-tool touch or a finish below 100% has not satisfied the stated condition. Restart Level 11 dirty and repeat that one air-only job instead of risking the completed seventeen-level route.