How to reduce credit card offers and mailings
The telephone number 1-888-5-OPT-OUT (1-888-567-8688) was set up to establish a single point of contact for consumers to call to request that all three major U.S. credit bureaus (Equifax, Experian, TransUnion) remove consumers' information from the marketing lists and pre-approved credit offer lists sold to third parties. By entering your information, you prevent the credit bureaus from releasing your personal information to credit card companies. As a result, you should receive fewer credit card solicitations in the mail.
Also, it is ok to enter your Social Security number when prompted for it. The system needs that to verify your identity and remove you from the lists.