What's the best way to clean your head? Specifically carbon build up on the bottom of valves, for example.
Re: Head cleaning
valves - put them in a pillar drill (make sure the chuck is a good one though, so you don't risk scoring the stems) - and get a stanley knife blade on the worst of the crud.
then get some 240 grit paper and polish it as much as you want - don't go heavy on the seat area, obviously.
finally, go up to 400 or 600 grit, and high speed for a really good finish, if you're that fussed.
and make sure you don't go onto the part of the stem which sits in the guide.
you could then dump them in the dishwasher / ultrasonic bath etc etc if you want them really really clean... slightly diminishing return though, lol.