– start by using fine grained aluminium oxide sanding paper with a grain size of 240. The area with the scratch can be sanded until the scratch has disappeared. Make sure the sandpaper is wet frequently.
– make the surface dry and check if the scratch is gone.
– afterwards polish the surface with aluminium oxide sanding paper grain size 400.
– than dry the surface.
– finally maintain the bath or basin with the 3M ScotchBrite sponge that is delivered with the bath or basin.