When and if you encounter any old jackets, back packs, wallets, hand bags... always, ALWAYS check every pocket.
Just the other day I found a bag full of old clothes, within there was an old purse and the little pocket on the back had within it a crisp forgotten fifty dollar bill. A jacket within that same bag had $1.25 in quarters in one of the zipped up pockets.
I remember putting on my winter coat in the fall as a child and discovering pockets full of soiled tissues and occasionally money. So don't forget to check your own pockets.