If you partake in Bingo or Deal or No Deal and the likes, these are also charges to your onboard account/OBC. There are plenty of ways to spend it. However, my last cruise on Celebrity I had several hundred dollars of non-refundable credit left after settling my onboard expenses. I went to the casino and tested a theory. I charged $100 to my casino account (or whatever it was called) at the slot machine. I played for a while. I was up. I was down. I was up, down, up and over my original $100. I cashed out at the casino cashier and received cash. I did this for the remainder of my non-refundable credit. I happened to come out just a little bit ahead. I have seen on other threads that the key to being able to cash it out is that you have to actually BET the entire amount. Not all at once, but over time. So sitting at the slot machines for awhile, up, down, up, down, etc, you end up actually betting quite a bit, even if your net gain is very little if anything at all. Even if you end up losing some of it, It's better than just leaving it unused in your account. Something is better than nothing. And it's fun.