WAS your rag covered with black material? If so, previous post is probably correct. But, perhaps the chemicals and solvents in the product you used got into/under the finish, probably lacquer, and "flashed" it. Might be temporary if it softened the finish and may turn dark black again when the absorbed solvents dry out. But, maybe not. Polishing compound, not "cleaners" may help, but you may be stuck with what you have.