I had my carbs off recently and happened to look down at my valves and noticed all the crap on them. I've been running some carb/valve cleaner for a while in small doses and it doesn't seem to be doing much. Anyone got a proven way to do a good cleaning w/out removing the valves? Heard a crazy theory from a mechanic once about poring a small amount of water through w/ the engine WFO, but was scared to try it.