we've recently started to clean out the crap and replace it with a couple things ... found one and it had this big load of hair in it, like dog hair or something, found batteries in another .... we just trash it, so the next people dont have to come across it. we also try to clean up the trails abit along the way. we try to trade 1 for 1, we usually have a big bag of stuff we take along, caching with kids means they want to find something, and I feel responsible to replace what is taken. remember its the few and not the majority, or so i choose to believe!