You can deposit any check made out to cash into your own bank account, just like the coins and bills it represents. A $20 check made out to cash is treated like a $20 bill at the deposit window. You don't have to prove your identity to deposit it. The only catch is that it still has to clear the other bank, like a check, or you will not get the money.
Payable to Cash
Making a check out to "Cash" means whoever holds the check can cash it. This is an option when someone makes a payment but is not sure who to write the check to, or wants the recipient to have flexibility. However, this also means that anyone -- not only the recipient -- could deposit the check. So keep this check safe, as losing it is like losing cash.
Depositing the Check
You can deposit the check into your bank account, similar to any other deposit. The bank may ask you to endorse the back of the check just to document who cashed it. It must make the deposited funds available according to its stated policy and be in compliance with Regulation CC. If the amount of the check is more than $5,000, a hold can be placed on the amount exceeding $5,000 for a "reasonable" time. Unless you specifically ask, banks are only required to tell you about a hold on the funds if the time will exceed normal limits.
Endorsing the Check
It is a good idea to endorse the check as "for deposit only" on the first line and signing your name below this. You can also write your account number below your name, although this could be a security issue if the check is lost. By endorsing it this way, you are putting a restriction on the check. It then can only be deposited into an account in your name.
Many banks offer the convenience of mobile banking, including making mobile deposits. Check with your bank to make sure they will accept a deposit if the check is made out to cash. Do the same before making an ATM deposit. For example, PSECU, one of the largest credit unions in Pennsylvania, states on its website that only checks made out to your name can be deposited by ATM. Checks payable to cash are not accepted for deposit via that method.