I found a credit card last time I was in toronto - on a public sidewalk between Roy Thomson Music Hall and Wellington Street and popped it into a night depository box for the bank that issued it. It may not get back to the person it belonged to - but it was not going to be used fraudulently, either. I am never sure how to handle such things, but I think making sure no one can use it( in the case of things like credit or debit cards) - or turning it in someplace where it has a chance to be returned to the owners is the right thing to do