Many, many years ago, back when everyone ran a K&B .40 in quickie 500 racing, I experimented not with Slick 50, but another teflon additive. This stuff was applied by running your engine rich and dribbling it into the intake. The teflon mechanically bonded, was pressed into the lining, during the run. It actually gained me 200-300 rpm, but the teflon did coat the plug element, causing poor running after 5-6 flights. Since I was running a new K&B 1L plug with every flight in a race and using the old ones for practice, this didn't bother me too much. These days, plugs are a lot more expensive and last much longer so I don't think it is practical to use.