This is probably due to residue from hard water. Fill the pot with Ammonia and allow to stand for a few days. Then use some elbow grease with a hard bristle brush or scotchbrite. This should remove the residue.
This is probably due to residue from hard water. Fill the pot with Ammonia and allow to stand for a few days. Then use some elbow grease with a hard bristle brush or scotchbrite. This should remove the residue.