Music teacher Marybeth Norby asks:
"Walla Walla (WA) is very hot and dry. My marimba bars, especially the Aussies, are looking very dry. Is there an oil that I can put on them to keep them moisturized but won't change the pitch?"
Answer: Absolutely, you can re-oil your bars if they are getting dingy or dry looking. Of course this applies to the entire instrument, but in regards to the bars, I would not overdo it - for instance don't be oiling the bars every year or something. I have heard theories about over-oiling affecting the tone, and I am skeptical, but really the wood is pretty durable oiled or not, so I would just put on the least amount you would need to re-vitalize it. Before doing that you should wipe the bars clean with a very slightly damp rag, just to get the accumulated muck off.
Tung oil, Danish oil, Teak oil, any variety will work, but I would rub it on with a rag, don't be flooding the bar surface with oil.
As far as all the things that might change the bar pitch, this is probably pretty low on the list, as long as you don't overdo it. Chances are if you've had an instrument for a few years, many of the bars are already slightly sharp or flat, and the effect of any added mass of oil would be noticed in terms of a cent or two, not a generally noticeable pitch change.
