Don't use Waste Oil, don't even think of it please. You could be endangering yourself from a potential to overfire and have a serious melt down.
Veggie oil I've been told on this forum is used by some suppliers,
I'm partial to Peanut oil myself
If your from Providence RI, are you getting your coal delivered from Cranston by any chance? If so, ask Manny if he offers pre-oiled.
I have a ton of bagged Rice that comes in Nylon Burlap that allows water to pass through so I'll just spray a bag down with the garden hose and let it drain out.