I agree, the key to clean plugs is using 2 cyle oil that does not create fowling carbon on the plugs when it burns and using high quaility gas that burns completely. Remember all of the adatives in gas are designed for cars for premature detination, ping, spark rattle or dieseling of the engine.
The trace element, or gasoline smell you get in your clothes, hand, van and workshop that you hate, is so you can know that it is gas or so you have a gasoline leak. Try pure white gas or coleman lantern fluid and you plug fowling problems will just go away.

Here is a handy tip that really works I read in Field and Stream magazine over 20 years ago that was designed to get that "Fish Smell" off your hands after cleaing fish works for getting that gasoline smell off your hands as well: Wet your hands, us liquind soap and rub it in really good. Now, wipe the soap off your hands directly onto paper towles. Now go back and wash your hands using the same soap and rise with water again. Walaaa, the smell is gone!

George Jenkins, Troy Built Models.