Furniture, Wood and Cabinetry Finishing - How to clean finish on piano

The finish on my piano shows the wood grain as dark, but the rest of the finish has a greenish tint. It was originally a walnut finish, although I thought it looked more mahogany because there was quite a bit of red in the finish. I don't know if it has a lacquer or polyurethane finish. I orinally thought it may be a wax buildup. I have used a little Murphy's Oil soap on it. This really dulls the finish where I have tried it and am afraid I may be causing damage, so have ceased to use this. I have also tried Old English lemon oil to clean it. It takes a lot of rubbing, with very little or no change in the look of the finish. Some parts of the piano have no wood grain showing at all, but just a dull greyish brown. I have had this piano for 30 years and have taken good care of it. I have usually cleaned it with Pledge or Favour products. I just noticed this finish problem two months ago, but play quite often so I can't imagine that I wouldn't have noticed it before. We also have electric heat in our ceiling. Could this be a factor? I appreciate any help you can give me.

Lee:

Murphy's oil soap will not harm any cured finish.

For cleaning in my shop, however, I use Naphtha. It's a fast drying oil-based solvent that leaves no residue, cleans oil dirt grease, etc, and will not harm a finish. Try this follwed by a good paste wax - say on the top, or the sound panel beneath the keyboard for a test.