how do you properly clean a spark plug . . . . i was playing with my carb a little today, and in the process fouled a plug. i took it out, sprayed it with some simple green, wipped it off as much as i could and put it back in. It started but died immediatly. So i took it out again, soaked it in some heavy duty degreaser, wipped it with a soft wire brush, dried it and put it in.. Doesn't fire at all. . . . . . how do you properly do it?.