With all the credit card programs on the market, when you pull out your plastic, you can earn all sorts of rewards. Some credit cards give you cash back on purchases. Others allow you to save for college. Still other co-branded cards allow you to earn special rewards like points to use at retailers, airline trips and hotel stays.

But what if you want to use your plastic for good? You can, if you add an affinity credit card to your wallet.

Affinity cards are credit cards that allow charities to raise money without having to do the legwork of extra fundraising. The charity works with a credit card issuer to produce a card with the charity's logo on it, and every time you use that card, a percentage of your purchase goes toward your charity.

Bank of America is one issuer with an affinity card program. Its affinity cards and banking products support a number of environmental organizations whose values Bank of America also subscribes to, including The Nature Conservancy, Sierra Club and WWF/UK.

Bank of America also offers a credit card that benefits the Susan G. Komen for the Cure charity that contributes money toward the fight against breast cancer. This Visa card also offers some cash back rewards to customers.

With each of these cards, a small percentage of each of your purchases is donated to the corresponding charity.

While Bank of America has affinity cards tied to specific organizations, Capital One has an affinity card program for organizations of all sizes. This program, called Capital One Card Lab Connect, is geared toward charities, professional societies, community organizations, churches and schools who want to have an additional stream of fundraising revenue by having an organization-branded Visa Platinum card.

The Card Lab Connect program is free of charge to qualified organizations, but these groups must go through an application process in order to be allowed to participate. Once approved, an organization can create up to three credit card designs that include the organization's logo. Then the group promotes their credit card through a special Card Lab Connect website.

Additionally, participating organizations are not required to share their membership lists or financial information with Capital One, nor will they receive a list of people who have signed up for the credit card.

Once the organization has its program all set up, it can track card contribution through an online management tool. Capital One then makes quarterly payouts within 60 days of the end of each fiscal quarter.

The organization's supporters then apply for the credit card through that site. Capital One approves the card applicants the same as it does for the other cards in its portfolio. Once a customer receives and uses her card, the organization receives a $50 first person bonus. After that, the organization receives two percent of gas station and grocery store purchases, one percent from other purchases and up to ten percent of purchases made at select merchants.

While it may not sound like a lot of money in terms of percentages, it can add up. If an organization gets the minimum recommended number of cardholders, which is ten, and every holder uses the card fairly regularly, it could add up to a few thousand dollars of extra revenue for a charity.

One thing to keep in mind if you do have an affinity card is that the money donated to the organization through your spending is not tax-deductible. However, if you care about a cause but don't have a lot of extra cash to make a monetary donation, this can be a way to support a good cause.