When I was in college I would do this with all the credit card offers received, or anything else I found offensive, if it had a return envelope. All the paper t

When I was in college I would do this with all the credit card offers received, or anything else I found offensive, if it had a return envelope. All the paper they sent would go back in the return envelope, along with a handful of pennies, and maybe a guitar string or two taped across the top flap. I'm sure most of them cost several dollars in postage to get back.