In a Washington, DC, suburb last week, a man walked up to the Wells Fargo ATM he used a couple of times a week and something didn't seem quite right. The card slot looked different.

He was about to slide his bankcard through the slot when he said something made him hesitate. Instead, he gripped the slot and jiggled it, shocked that it came loose in his hand.

What he held was not the housing to the card slot but a "skimmer," a device to read the card's magnetic strip and transmit the data to a nearby thief. The thief has simply placed it over the ATM's actual card slot, hopping to steal hundreds of bankcard numbers.

Hundreds of miles away in Ohio, Attorney General Richard Cordray has received a number of reports turning up at ATM and gas pumps. He cautions all consumers to be very careful when using debit and credit cards.

"Skimmers are designed to steal debit card numbers and corresponding account information stored on the card's magnetic strip. They often are camouflaged to fit gas pumps and ATMs, and they may be equipped with hidden cameras," said Cordray. "The cameras take snapshots of debit card PIN numbers as consumers enter them. Once the scammers have acquired the account information, they use it to make unauthorized purchases and withdrawals."

Cordray said that with this scam, awareness is the best defense. It can be difficult to avoid the scam entirely, but consumers can mitigate the effects by carefully monitoring their accounts and limiting the places they use their debit cards.

Cordray suggests consumers closely watch their bank statements and track debits closely. Watch for any unauthorized withdrawals or otherwise suspicious activity.

Advice

Your chances of avoiding this scam are better if you use one ATM and one gas pump on a regular basis. That way it will be easier to track which machine has been equipped with a skimmer.

Try to use an ATM that is located in a very public place or is located inside a bank lobby. Scammers are less likely to tamper with machines in those locations.

Finally, when using your bankcard, choose the "credit card" option instead of "debit card." It will be more difficult for scammers to make unauthorized purchases without your PIN.

Skimming can occur with credit cards as well as debit cards. Because of this, consumers should pay close attention to their credit card statements to watch for any unauthorized activity.