About 25 years ago, I installed a one piece, banjo shaped, cultured marble sink and countertop bathroom unit. Now, the bottom of the sink is lined with small, discolored cracks. This area, which surrounds the drain, is very rough , and extends a couple of inches from the drain in all directions. Other than this, the countertop is in great shape.
Is there any way to repair (sand down ? fill the cracks? re-glaze? ) the bottom of these cultured marble sinks ?