METAIRIE - Once again, authorities are warning debit and credit card holders about skimming machines on gas pumps and ATMs.

Skimmers are devices that are illegally placed over the strip reader for debit and credit cards. The devices store card numbers that are swiped through them for thieves to then use to clear out bank accounts.

The renewed warning comes after a gas station worker in Metairie discovered the devices on two of their pumps before the suspects could retrieve them and the data collected on them.

The latest incident is hitting home for a lot of people as the location is on the corner of North Causeway Boulevard and Galleria; a high-traffic area that feeds right onto I-10 in both directions and toward the Causeway Bridge.

"Skimming devices are meant to be mobile," said Jefferson Parish Interim Sheriff Joe Lopinto. "They'll be out here for a few days and then they're out in a couple days. They come in, gather as much information as possible, then they leave. They'll go put it on some place else in another city or another state."

A week before the Metairie skimmers were discovered, an unpaid $7 Waffle House tab turned into the arrest of two men in Pearl River who police say were found in possession of skimming devices, fake ID's and counterfeit credit cards.

According to the Secret Service, so far this year, more than 75 skimmers have been recovered in Louisiana by local, state and federal law enforcement agencies, protecting more than 9,000 bank card numbers and preventing more than $4.5 million in potential fraud loss. However the Secret Service says they believe that only represents about 20 percent of the skimmers actually out there.

So while authorities have stepped up their game to intervene and save stolen numbers, they say, unfortunately, the burden is primarily on the potential victim to protect themselves.

"Here, you can end up pulling on this device, make sure there's nothing here," said Lopinto, who demonstrated tips to use while at a gas pump. "Check the device itself, make sure there are no cameras. A lot of these skimming devices will have cameras attached to them so they can catch your PIN number after you put in your magnetic strip."

If you ever find a device anywhere, make sure to alert the business, then call 911. If you find your account compromised, after contacting your bank, report the situation to your local law enforcement.