[kevkrom]

Was it a "Business Reply" postage paid type card? If so, tape it to a brick (address side showing) and mail it back to them. The USPS will charge them for the weight of the card. They don't care about anything it is taped to.

The USPS will treat anything that obvious as trash, and not levy a charge. You're better off just returning (blank -- make sure you get rid of anything that IDs you) cards.

[AFreeBird]

The USPS will treat anything that obvious as trash, and not levy a charge.

Once upon a time, I worked (IT) for a direct marketing company. I've seen brick/cards delivered by the USPS before. Now that was some 15 years ago, but they did deliver it.

Technically it is a properly address and postage paid "package". They may have modified their rules, I don't know.