Without knowing exactly what product created this problem, I can't give you any definite diagnosis. But I talked to someone at Kohler, and she said that if the faucet is tarnished by the product, probably the only way to remedy the situation would be to replace the faucet. Wipe the entire surface completely dry with a clean soft cloth.
Many cleaning products contain ammonia or other chemicals that can damage the faucet finish.
I realize this probably doesn't solve your problem, but it may be helpful for future reference.