Someone may have used a solvent based cleaner destroying the finish coat? If the lacquer is still good you might try a wax. I have no experience with Cory products- I use mother's spray detailer and an ultra soft microfiber cloth for lacquer and keytops. Lets see what Yamaha has to say... > Hi all. I recently removed about a ¼ inch of dust from a church’s Yamaha > grand. There were lots of fingerprints on the fallboard so I proceeded to > put on some Cory polish that specifically states it removes fingerprints. > (By the way, this is a lacquer finish.) Well, it immediately clouded up, I > tried buffing it off, it looked terrible, I applied some Cory wood cleaner > which made the wood look very dull. I talked to the Cory people who said it > was probably reacting with a previously applied oil-based polish and I > should apply a little Windex to remove the oil. When I applied the Windex > nothing happened. The fall board basically looks like someone removed the > shine.
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