We aren’t so plagued as we used to be, which is probably a sign of the global downturn, but we used to get about 5 credit card offer letters everyweek and we still get the occasional one. I find these unsolicited spam letters a real pain so I used to deal with them like this.Open the letter and tear off any identifying sections with my name and address on. Then get the prepaid envelope which is supplied to accept the offer and put all the contents in along with the original envelope the whole thing came in and post it all back the the credit card company. If you can find any other junk to bulk the envelope up so much the better.
I always thought that at least that way they have to pay not only the postage to originally get the letter to us but also the cost of the return postage and the salary of someone the open it and throw it away. Perhaps if everybody could increase their costs this way there might be less unsolicited junk through our doors.