Well, today I found three credit cards on the pedestrian walk. All three still useable till '13 and not damaged. So I took those and brought it to the police station, which was just 5 min away, thinking someone got robbed and the thieves just threw away the cards. Left them at the station and gave one officer my IDs and phonenumber etc. So some hours later I get a call from a man, finding out it's the owner of the cards. He wasn't robbed, he lost them while taking some money from his wallet, not noticing that he lost his cards. And he wouldn't have noticed until weekend (96 hours!) if not for the police who called him because of the cards. So he is hyper happy cause 96 hours is a long time for evil persons to use a credit limit. Says that he didn't believe that there are still people so honest.
I feel really good that I did what I did, cause I know it was the right and the most honorable thing to do.