NEW YORK (CNNMoney.com) -- My grandpa co-signed $60,000 in student loans for a relative. My relative is in default. The collection agency is now calling my grandpa. Can they put a lien on his house or threaten garnishment? He is retired living on Social Security. -- Mike

If you co-sign a loan and the primary signer can't pay, you are responsible for the debt. But rest assured, a collection agency cannot garnish Social Security payments.

They can get a lien on his property with a court order, but that's a long shot, according to the Association of Independent Consumer Credit Counseling Agencies. It's more likely they will go after the primary borrower. If you want them to stop bugging your grandfather, send them a letter. And while your grandpa may still be held responsible for the debt, by law, they must stop contacting your grandfather.

And if you think a collection agency has violated your grandfather's rights, report it to your state Attorney Generals' office and the Federal Trade Commission at ftc.gov or 877-FTC-help.

I work but my husband doesn't - we file a joint return. Can I still open a Roth IRA for him? Right now I have my company sponsored 401(k) and Simple IRA ( both maxed out) but he has nothing. -- Anonymous

We have an emphatic YES to your question. Since you file your taxes jointly, he can open a Roth IRA for himself.

As long as you make less than $160,000 in adjusted gross income a year, he can put in the maximum amount allowable - that's $4,000 a year (or $5,000 a year if he's over 50 years old).

Is there a way to opt out of the millions of credit card offers that seem to come every day in the mail? My shredder is working overtime getting rid of all the junk mail we get. -- Lisa, Florida

Absolutely. The credit bureaus offer a toll-free number that enables you to "opt-out" of having pre-approved credit offers sent to you for two years. Call 1-888-5-OPTOUT. You can also tell three major credit bureaus that you do not want personal information about you shared for promotional purposes. Here are the addresses:

Equifax, Inc. Options; PO Box 740123; Atlanta, GA 30374-0123

Experian Consumer Opt-Out; 701 Experian Parkway; Allen, TX 75013

TransUnion Name Removal Option; P.O. Box 505; Woodlyn, PA 19094

You can also get off lists at the Consumer Credit Reporting Industry Web site, at optoutprescreen.com

I am having a debate with my wife...She was told it is more energy efficient to run the AC all day. But isn't it better to use it only during time of need? Also, is it more cost effective to use fans or AC? -- Peter

Peter, you're in the right here. According to our experts, it's much more efficient to run the air conditioning only when you need it. It's definitely not cost-effective to leave your AC on all day. The good news is that you can compromise. Raising the thermostat on your air conditioner when you're out of the house will keep your home cooler during the day and won't put a huge dent in your budget. And yes, window fans use much less energy compared to air conditioners.

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