Mike Ferrara wants to buy a house in a few months and is worried that mistakes on his credit report will keep him from obtaining the loan he will need.

His concern is legitimate. You'd think with a credit score of 650, he'd be fine. But not now. With banks less able to lend money than they were before the housing crash, mortgage loans are tougher to get unless people have credit scores in the mid-700s or higher, on a scale of 300 to 850.

So Ferrara, who lives in Harwood Heights, Ill., is right to want to erase mistakes from his credit reports - the records three credit bureaus assemble to show lenders a person's history of paying bills. If Ferrara can get the credit bureaus to fix even one or two errors in his credit history, it could make the difference between receiving the loan he wants or not.

But Ferrara, like many consumers, knows nothing about the credit maze and does not want to bother figuring it out.

"Tell me who can do it for me, someone legitimate," he said in a telephone conversation last week. "I have seen mistakes in my credit report. But I don't have the time to work on it. I drive a truck at night and need to sleep during the day."

"Sorry, Mike," I had to tell him. "If you try to turn this over to someone, you might not end up sleeping easily."

Unfortunately, there are some slimy characters out there - firms that run ads making it sound as if they can make your credit messes vanish in a snap. If you have high bills and are trying to work on them, too often the scoundrels collect a few hundred dollars from you and still leave you with your problems. Sometimes, they make your credit score worse.

The Consumer Federation of America found in a 2003 study that many credit-counseling firms charge excessive fees, promise quick fixes that are deceptive, and provide improper advice. They put clients on payment plans they cannot afford, and sometimes collect money from clients without paying their bills.

The most reputable firms can be found through the National Foundation for Credit Counseling (1-800-388-2227, or NFCC.org), but they are not in the business of credit repair.

Too many credit-repair firms have a history of deceptive practices, and the Federal Trade Commission has charged several.

"You should be very cautious about using a 'credit repair clinic,' " said Evan Hendricks, author of

Credit Scores & Credit Reports: How the System Really Works; What You Can Do.

Instead, roll up your sleeves and go to work on your credit report yourself. Even if you were able to find reputable help, you could not walk away completely. Only you can start the process by looking at your credit report and spotting credit card accounts you never had or late payments that weren't late.

Begin by ordering a free credit report from each credit bureau through AnnualCreditReport.com. Do not respond to the ads you have seen for other sites that promise "free credit reports." Only AnnualCreditReport.com was set up under government rules to provide completely free reports.

You will need to look for mistakes in three credit reports, one from each credit bureau: Equifax (1-800-685-1111), TransUnion (1-800-916-8800) and Experian (1-888-397-3742). One bureau might be correct, while another might have errors. All three matter.

Sometimes, people find their report reflects accounts held by someone with a similar name. Other times, people find unpaid bills they didn't know were delinquent. Medical bills can show up in reports while people are still seeking payments from insurance companies.

You will not see a credit score on the credit reports. But the credit score reflects the payment history you see in your credit reports, so cleaning up errors should improve your score. You can buy your credit scores at MyFICO.com.

Credit bureaus are required by law to investigate all consumer disputes, fix errors, and inform you of the outcome within 30 days. Hendricks suggested using the official dispute form provided by the bureaus on Web sites and writing a short letter that states you are "disputing the following inaccuracies." State why, and give the account, account number, your name, address, previous address, birth date, Social Security number, and supporting documentation.

Send a certified letter with a return receipt, Hendricks said, and send a copy to the credit card company or other firm that was erroneous in your report. Then file it all in case you are unsuccessful and must pursue the matter further.

The credit bureaus investigate disputed records electronically, and often the system fails to detect mistakes when they have occurred. Cases involving identity theft or divorce can be especially tricky, Hendricks said.

At that point, you may want to get legal help, he said. If you do, seek a lawyer with experience in the Fair Credit Reporting Act through the National Association of Consumer Advocates (

» READ MORE: www.naca.net

) or the National Consumer Law Center (

» READ MORE: www.nclc.org

).