Only bank customers can cash checks at ATM machines. Even then, the ATM must have that capability. These machines are usually located at the physical bank branches. Other bank ATMs accept remote deposits but have a three-day holding period. Most banks now offer mobile check deposit. This feature is free and quicker than mailing your check to the bank or finding a local bank. If you're making a mobile deposit, make sure you check the "Mobile Deposit" box on the back of the check. Most paper checks now include this box as an extra security measure. You should also write "VOID" across the check once you're sure that your deposit has cleared.