For several months, we have a light ring that appeared unannounced on our coffee table..Roughly glass or cup bottom shape and the ring is lighter in color then the surrounding finish...This is a store bought, commercially made, rectangular coffee table (w glass insert) so I'm quite sure it is lacquer sealed...I have tried DA, an oil soak, light sanding and diluted dye. No great results..I' m about to surrender and sand down the whole top to bare wood and refinish..Any other techniques i should try prior to resorting to the sander?? Thanks in advance, Jerry