I use an old cat litter tray when stripping small assemblies like carbs and stuff. Spray can lids, butty boxes, tankards with glass bottoms etc are all put to use. Despite that I still drop stuff such as a small screw/spring/nut or bolt as I'm in the process of fixing it back into a bike mounted switch housing or summat it's always a massive triumph if ya ever find it again
We had a Chinese takeaway last night and have lots of empty boxes with lids - just looking for something to dismantle now.I save the plastic trays that our local Chinese takeaway supplies food in ( washed!) to act as parts trays. That makes sure all the bits are put back. If there's a bolt left over there's a problem somewhere!