I also have seen many empty Mason jars in the bottom of vertical pianos. Its my feeling that the surface area of the water exposed to the air is too small to have any real benefit, and without some method of infusing the moisture into the air (fan, heat, whatever) is does little good. Then, the adage "out of sight, out of mind" takes over, the owner forgets to fill the jar, and its ineffective anyway. Mike Kurta Auburn, NY Home of the Wegman piano
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