A good quality, stone safe soap film remover will be effective at getting rid of hard water deposits as well as soap scum. Sometimes a razor blade may be necessary as well to shave off the some of the build up. Check out www.stonecarecentral.com for excellent quality stone and tile care products.
Giovanni Lagana
Lagana Tile
www.laganatile.com
Natural Stone, Tile & Grout
Installation, Restoration & Maintenance