They have cleaner to use instead of the water now. I think one is called Seafoam, and I know Delco has one at GM dealers. They have a spray or a can. With the can, you use a vacuum line and slowly drain the can. When there's a little left, you stick the vaccum tube in there and let the engine stall out as it pulls in the last bit. Let it sit 10 minutes, fire it up, and it's supposedly clean.