The methodology ASTM Designation C 1378-97, was used to test the resistant to staining. This test is based on a standardised test method for determination of ceramic glazed wall tiles. The resistance to staining was tested by exposing a staining agent to the surface of a tile for 24 hours. The standard stains are removed in a defined way using increasing strength of solvents. Results show that even very severe staining can be almost completely removed.
