Why do some cellos turn brown?

[T.G]

Originally Posted by The Poet

Always figured that the first factor, not the last. In any case, I always figured it a good sign.

They weren't listed in any particular order, but you want to get technical about it, age is actually a culmination of many of the other factors combined.

I once turned a pile of used but still clear cello to a dark amber resembling cello found on cigars 10-15 years old in a matter of just a few weeks just by sealing them in a tupperware with a ramekin of ammonia and setting the tupperware where it would be exposed to some heat.