In System 7, items dragged to the Trash are not deleted until you select
Empty Trash from the Special menu. If you drag items from a floppy to the
Trash, those items will appear in the Trash whenever that disk is inserted,
until you empty the Trash.
If you insert a disk that has some items in the Trash, the Trash icon will
bulge when you insert the disk to let you know this disk has items in the
Trash.