MIAMI VALLEY — Credit card skimming machines have emerged in Miami Valley and they are more advanced, harder to detect.This week police put Miami Valley residents on alert concerning high-tech thieves. Bad guys using credit card skimmers to steal your card number, your personal identification number — and ultimately your money. Experts say these skimming devices are getting more high tech each day. They easy to buy and easy to install and starting to look more like the real thing.This week's discovery of a credit card skimmer inside a gas pump at a Montgomery County Murphy USA, brought the reality of high-tech theft home.Gas stations aren't the only places where you and your card are vulnerable. 46% of skimmers are found at ATM's.I've seen the devices. Dayton's Michael Rumsey told us while getting money out of a machine downtown. They're clear. Plastic.Michael says he knows what to do:Go to a different one. It's pretty simple. But its not always that simple. John North of the Better Business Bureau says signs of skimming devices are hard to recognize.Shake it. Make sure it's not loose. Don't use it f it looks broken or tampered with, North explained.And some ATM's are more secure than others..''If it's not a bank I don't mess with it! No ma'am, Pricilla Smith told us confidently. Pricilla has the right idea. Independent stand alone machines are hands down the easiest to tamper with. When you have that option, you use your bank. You use a bank ATM machine, North advised.Bank ATM's are undoubtedly safer, but there are still some things to be aware of. Skimming devices can be placed over card readers and in some cases entire panels and even keyboards can be replaced with fake equipment.And always, if you don't feel comfortable just walk away.