I arrived at a bar/club once that we used to play about every six weeks and the owner held up a BLACK-painted 50cal can and asked "any chance this belong to you?". It did, and had not yet been missed, I think it had some almost-never used spares/adaptors in it. That can was painted ORANGE the following week. 
In my sound-running days, I'm embarrassed to say I once left a box under a mix riser that had a three-station intercom system and two spare horn diaphragms in it. I never saw those again, but all of it belonged to me, so my bad, my loss.
In my sound-running days, I'm embarrassed to say I once left a box under a mix riser that had a three-station intercom system and two spare horn diaphragms in it. I never saw those again, but all of it belonged to me, so my bad, my loss.