Trashcan stores files that are dragged onto it. They can then be restored or deleted.
It complies with the freedesktop-trash-specification.
If you want it to change its icon when its status changes (full/empty), you must use ROX-Filer >= 2.5. If you got Trashcan via AddApp, you must create a file "~/.config/rox4debian.berlios.de/Trashcan/wrapper" that contains the path of the wrapper generated by AddApp.