here is one of the best advice i got on "How to piss off credit card companies" (taken from maddox.com)

Here's a little secret that might piss off credit card companies and potentially get them to stop harassing you with upwards of 20 credit card applications per week. Some people have known this for years, and since a fair amount of people will read this I feel that it's my duty and obligation to share this secret with you, because based on the email I've received, I don't always get the sharpest tools in the shed reading my site (as opposed to the regular tools who read this site). For the slow: I'm saying that you're stupid and wouldn't come up with this idea on your own; pay attention.

There are two types of junk mail that everyone gets: coupons for stupid bullshit that you don't want, and credit card applications for credit to buy stupid bullshit that you don't need. Here's how to take care of all your junk mail in one fell swoop: use the postage-paid envelope that credit card companies send you with their applications to send them the OTHER junk mail you receive. It's just that simple. Imagine the frustration of credit card companies when they have to spend millions of dollars every year on first-class postage just to open up an envelope and find Pizza Hut coupons inside. The envelopes are intended to be used for "BUSINESS REPLY MAIL," and so use them for their intended purpose. You're sending them valuable money-saving coupons which could mean big savings to credit card companies, and it makes good business sense to use them. Consider it a reply to their business proposition with a business proposition of your own: 35 cents off a large, one-topping pizza. In fact, they should be thanking you for giving them these money-saving opportunities. Or how about sending them credit card applications from other credit card companies? Be creative