“Banks are always looking for ways to raise revenue, so they’re competing for your business,” says Tim Chen, the CEO of NerdWallet.com, a credit-card resource site. Shrink your junk-mail pile by taking these steps: First fill out a form at OptOutPrescreen.com, a joint venture of the consumer credit-reporting agencies. Then enroll in the Direct Marketing Association’s delete list. These two services will block offers for five years.