Dear Mary: You have said that it's important to keep our credit cards active even if we keep them at zero balance. How often should we use them to keep them active? Does it matter how much we put on them? Will making small purchases and paying them off immediately suffice? — Nancy

Dear Nancy: Using a credit card twice a year is more than sufficient to keep the account active. The amount you charge is unimportant. You can even purchase a 99-cent mobile app! Whatever you charge, pay it off right away — that very same day — so you won't forget and run the risk of letting a silly, little purchase become rolling debt.

Your bank doesn't look at purchase amounts or the length of time between purchase and payment; it simply records that a transaction was made and the payment was received according to the terms and conditions.

These days it's important for every adult to own one good, all-purpose credit card to maintain a high credit score. But you don't have to use that thing habitually or carry a smidgen of debt around to do so. You could purchase two mobile apps a year for just $1.98, pay it off immediately and build a killer credit score. It's that simple. I have a feeling that's exactly what you plan to do. Good for you!

Dear Mary: I've heard that adding someone to your credit card account will help that person establish a credit history, even if they do not use the card. Is that true? How would I go about doing this? — Pat

Dear Pat: It is true. You can add an adult as an authorized user by calling your credit-card issuer customer service. (The toll-free number is on the back of your card.) An authorized user has all the privileges of using an account without any liability for repayment. I know it sounds crazy, but that's the way it works. Account activity is reported to the credit bureaus and also goes into the files of the primary account holder (you) and the authorized user. That means the authorized user piggybacks on your good credit. Just keep in mind that this could backfire if your authorized user decides to go nuts and run the balance up to or beyond your limit. Not only would you be liable for full repayment but that negative activity will also go in your credit file. I hope that helps.

Dear Mary: I love all of your wonderful tips. Can you help me? I just moved into my first apartment after living in a big home for many years. I have melamine cabinets, and they're dirty. I've cleaned them with Blue Dawn and water, but they still look streaky and dingy. How do I make them shine? Help! — Katy

Dear Katy: I assume you're renting, so you probably don't want to paint the cabinets. There's a remarkable product called Cabinet Rescue (available online and in stores like Home Depot) made specifically for melamine. Clean the cabinets well. I'd follow with a good furniture polish like Lemon Pledge. That just might do the trick! But if you're still not happy, spend a few bucks on one of my favorite kitchen products: Johnson's Jubilee Kitchen Wax. It will clean and polish everything in your kitchen, including the melamine cabinets, Formica countertops and appliances, too. I love the stuff, and I think you will, too.

Mary invites questions, comments and tips at mary@everydaycheapskate.com, or c/o Everyday Cheapskate, 12340 Seal Beach Blvd., Suite B-416, Seal Beach, CA 90740. This column will answer questions of general interest, but letters cannot be answered individually. Mary Hunt is the founder of www.DebtProofLiving.com, a personal finance member website and the author of "Debt-Proof Living," released in 2014. To find out more about Mary and read her past columns, please visit the Creators Syndicate Web page at www.creators.com.

Photo credit: Blondinrikard Fröberg