I know what you mean. I've had the same problem. The best I can suggest is to go when they aren't busy, like 2AM to 8AM, and not on weekends. If you don't have a line of impatient people behind you, most Vegas cage cashiers are very helpful, I find, even searching for better condition pieces. And a toke (tip) will get you a big thank you and make things easier for the next chipper that comes in there.