I have one of the old performer grills with the small 5lbs propane canister. I fill it maybe every couple of years... and it is a pain. Most of the filling stations give it a weird look and don't know what to do with it. They also try to charge me the flat filling price even though it is 1/4 the size. The last time I filled it up, the guy said the canister should expire by the next time I need to refill it. I cannot find a new one at a reasonable price. Can I modify the old Performer grill to work with the disposable canisters used with the new models?