Credit card skimmers are nothing new, yet people unknowingly fall victim to them daily.

Last week, an officer found one on an ATM at a convenience store in the 3400 block of West Colfax Avenue.

When he saw the loose scanner on the machine, he gave it a light pull and revealed a second scanner attached to the machine.

It was a credit card skimmer.

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Credit card skimmers are malicious card readers that grab the data off the card’s magnetic strip. Criminals harvest this stolen data from these readers and can use it to create cloned cards or hack into bank accounts to steal money.

Some skimmers are so sophisticated that they don’t prevent ATM or credit card readers from functioning properly.

Check out these tips from the Denver Police Department on how to spot a skimmer before you become a victim:

1. CHECK FOR TAMPERING. Examine any ATM or gas pump before you insert your card. If something appears off or inconsistent with the rest of the machine (color or materials used), don’t use the ATM. Also, give the keyboard a look-see. If it feels thick, like a protector was placed over it, it may have a pin-snatching overlay.

2. PUSH AND PULL AT EVERYTHING. ATMs and gas pumps are solid machines and nothing on the machine should jiggle or be loose. Push and pull at the protruding parts, like the card reader and the keyboard. Also, when you insert you card into the reader, wiggle it. This will foil the attempts of the skimmer to grab the data from the card.

3. BE AWARE OF YOUR SURROUNDINGS. When entering your PIN, cover the keypad to prevent someone from nabbing the digits over your shoulder. Also, frequent busy ATMs and grocery stores. Outdoor ATMs and less-frequented stores are more likely to have machines that have been tampered with, because they are more accessible to thieves.

4. USE NEAR FIELD COMMUNICATION (NFC) TRANSACTIONS. NFC transactions, such as Apple Pay, Samsung Pay or Android Pay, tokenize credit card information, protecting personal information.

5. USE FRAUD DETECTION SERVICES. Most banks and credit cards will reach out to customers should they notice something suspicious on your account. Pay attention to these alerts. Catching any criminal activity early will help you put a stop to it and recover any lost funds, should you become a victim.