I worked at a client where they photocopied their cash. If a customer paid for something in cash, or if staff came back from an event where cash was collected, they fanned those bills out on the copier glass and took a picture of them as backup documentation for the deposit. I’m not recommending this method, which doesn’t make much sense because cash is fungible (those nineteen dollars could be anyone’s nineteen dollars, so you’re not really creating reliable documentation), but it actually came in handy from time to time when I was sorting through a pile of deposits and got confused.
Instead of photocopying them, I record cash deposits with an Excel spreadsheet that totals up bills and coins by denomination. This may not be any more reliable as backup, but at least it’s tidy, and you can note on the spreadsheet when and where the cash was collected. And it saves you having to arrange a bunch of twenty-dollar bills on a copier and possibly lose one of them in that little space between the hinge of the lid and the wall. You can download my template to the right.