I guess it is personal preference. I don't clean mine very much, just when they get really caked - like every other year or so. I guess if you flew a lot you could clean them every year.

For the blue color, I am assuming it is a powder coated process. I think if it is worn off, there is no hope of getting it back. I never tried it, but I assume that the crock pot method would harm the powder coated surface.

Jeff A