The trunk itself consists of a large blue box with a lid, all dotted with various stickers. Items placed into the Janitor's Trunk when the player exits the level via the Punchomatic will spawn inside the trunk when they enter the Office, allowing players to collect items from the various levels.
Placing any item into the trunk will cause that item to be transferred between levels or back to the Office. This is true for any movable object, including objects that do not fit in the trunk itself, such as the Big Banger Supernova or J-HARM. In fact, as long as any part of the object is within or even on top of the trunk, the entire object will still be transported.When attempting to transfer larger objects, it is recommended to close the lid after the object has been balanced on top of the chest. In most cases, this will prevent the object from falling out under minor force.
If an item placed into the trunk does not fully fit (too long, too wide, etc), once the lid is closed on it, or once it is transferred to another level, the object can often be seen clipping through the chest. This can make the item potentially difficult to remove, or cause it to be "stuck" to the trunk. Grabbing the item inside the trunk with the hands and "shaking" them both around can help separate the item from the trunk. Use caution however, as the objects can "bug out" and start flinging themselves (and the player) around the room in an attempt to un-clip themselves.
As of version 0.45, players can also bring items from the Office to a level of their choice by placing the item inside the trunk in the Office and then starting the new level. Prior to the update, the trunk only functioned one-way, to bring items back to the Office.
- In order to successfully collect items and bring them to the Office, each level must be completed at least well enough to avoid getting fired. Leaving the map via the menu will not save the item, and punching out without doing an adequate job will result in the player being fired, causing the Office to be reset to its default state.
- If the Janitor's Trunk in the Office is vaporized through the use of the Laser Welder (which can only be brought into the Office via the trunk itself), dropped down the disposal hatch, or otherwise removed from the level, items transferring from other levels will still appear in the Office, inside a newly respawned trunk. Vaporizing the trunk in an actual level will simply cause the trunk to disappear, meaning the player may not collect items from that level. However, it will still respawn in the Office and other levels, or if the level in question is restarted.
- Players may move the trunk anywhere in the Office for convenience, while the trunk will still function normally.
- Any objects placed within the Janitor's Trunk will be detected by the Sniffer, but will not be registered upon completion of a level, and therefore will not affect the player's score.
- Originally, any item simply touching the trunk would be brought to The Office. This was later changed in an update so that only objects inside or on top of the trunk are transferred.
- The trunk's latch originally acted as an independent object, hinged to the lid. This would frequently cause errors, primarily in multiplayer mode, where the hinge could become stuck or cause lag. It was eventually completely removed, and replaced by a simpler version with the latch being a part of the lid itself.
- A variation of the Janitor's Trunk can be found in the hidden area in Unearthly Excavation previously belonging to Bob. This trunk is nearly identical to the standard trunk in size and shape, the only differences being the bright red color and stickers on the outside.