Marble vanity unit etch removal and polish Marks of light etching on marble vanity unit were caused by acidic drinks and left discolouration of the stone. The stain was removed and the surface is polished to shine and sealed. 1 Marks are visible in the reflection on the stone. 2 Close up of one of the etch marks. 3 The Unit is completely polished to a perfect shine and sealed. see more repairs