Thieves use tiny hand-held credit card readers to collect the information on your credit card’s magnetic strip. Skimming is common in restaurants and stores where you turn over your credit card to pay. When a skimming device is full of hundreds of credit card numbers, these numbers can be sold or used to create fake credit cards. Skimming devices can also be placed over the normal card reader on an ATM to steal your data when you try to withdraw money.