I've never cleaned the buttons (they have never really been dirty).
The cabinet is not exposed to any sunlight at all.
I like the comment about burning it with a cigarette... gives the panel that "authentic", "real arcade" look. (Not really... I know... some of you are going to zing me for this.... but I prefer the nice, shiny, unscratched, look of a new control panel... over the authentic look of a dull, worn, 1980's cigarette burned panel

)
The arcade gets used mostly by the grandkids (and me)... those little, 4-5 year old, grimy hands must be eroding my button graphics... I'll have to insist that they wear special white gloves before playing.
