Chattanooga Police are warning residents about skimming machines found on local gas pumps.Skimmer devices read and memorize vital account information making users vulnerable to ID theft. These devices can be used by criminals on gas pumps and automated teller machines.Police say devices were found by a store employee during routine checks at a local gas station located in the Hixson area at 5012 Hixson Pike. Skimmers were found on eight of the ten gas pumps.Authorities are cautioning residents, if you see the anti-tampering seal has been broken or the machine appears abnormal, contact a store manager and don’t use the machine.Police also say, use your debit cards as credit.Since the credit option does not require a PIN the purchaser has greater protection. Paying inside with the cashier is also a best practice.