Make sure employees know each credit company's authorization procedures.
Be wary of a customer with only one credit card and one piece of identification, even more so if they have no identification.
Watch out for a customer who makes repeated small purchases that are under the amount normally requiring managers approval.
If you are suspicious of the purchaser make a note of the appearance, companions, any vehicles, and the identification presented. Call the police department.
Look for alterations on the credit cards. This is usually done by either filing or melting one or more of the numbers and re-stamping them. Both processes can leave faint imprints of the original numbers.
Examine the signature strip of the credit card. Criminals sometimes cover the real owners signature with "white-out" and sign over it. This is not difficult to spot.
Compare the signature on the card with the signature on the receipt. They should be reasonably similar even to the untrained eye.
Many fraudulent checks are not difficult to spot if the employee is paying attention. Knowing this the criminal may try to rush the employee through the transaction or feign anger to throw the employee off. Never let a customer control the transaction. When taking a check insist on proper photo ID and make sure the addresses of the check and ID match. Write down the address on the photo ID even if the customer insists that another address they give you is more current. Be suspicious of any checks showing the following telltales:
Checks numbered under 500 (New account).
Glossy rather than dull finish of the magnetic ink on the bottom of the check
No perforation on the check edges.
Out-of-area banks or payroll checks on unknown businesses
Signature that doesn't match the spelling of the imprinted name on the check or the ID provided
Spots or alterations of the check's color or background