I am working mahogany for the first time, beautiful wood, works nicely, I can see why it has been a preferred furniture wood for several hundred years... anyway:
Now that it is sanded (60,80,120,150,220,320), there are white marks showing up. They look vaguely like scuff marks but I cannot sand them out, nor can I feel them with my fingers, but I can see them. When I wipe the wood with mineral spirits the white 'scuffs' disappear. They are not uniform but most of them are in one board (the center board of my tabletop). Is this similiar to the rays that appear in quartersawn oak or something else? thanks,