We used to use the cheapest pump spray glass cleaner (cheap Windex). It's mostly water, alcohol and dye. Warm engine, put on highest fast idle - about 2500 and spray it in about as fast as you can squeeze the pump without stalling engine - use about 1/2 the large bottle. Take off fast idle, spray in and stall engine. Let sit for 10-15 min, re-start, and run at about 2000 for about a minute.

The nice thing about doing it this way is you can control the liquid better without having to worry about locking the motor up.