if there is a layer of enamel: using grain size 800 sandpaper, carefully abrade the part of the surface on which the test is to be conducted without exposing the underlying iron surfaces.
Repeat this setence, but with the correct capitalization.
If there is a layer of enamel: Using grain size 800 sandpaper, carefully abrade the part of the surface on which the test is to be conducted without exposing the underlying iron surfaces.