Our company accepts pre-paid funds from customers in return for discounted rates. They sign a contract that states the credit balance is good for one year, and if the money isn't used in that year, it expires (unless they are an active customer).

Problem is, some customers give us money and forget about us. A couple of months ago, we got this list and called every one of them to let them know they had a credit balance.

Three months later, there is still a few credit balances.

I want to recognize this revenue to get it off our liabilities sheet, but I don't know how.