Common use of Basic cleaning Clause in Contracts

Basic cleaning. The Department of Historic Resources recommends that monuments be cleaned with nothing stronger than clear running water and a soft, natural-bristle brush, using circular motions to avoid abrading the monument. If soiling or biological growth does not respond to this method, the Department strongly recommends contacting the Department or a conservation professional rather than utilizing any commercial cleaning products. a. The black crust often visible on marble monuments cannot be effectively treated – it is an environmental byproduct resulting from a chemical reaction between the marble and acid rain. Attempts to remove this crust will result in damage to the underlying stone. b. Mosses may sometimes be removed by thoroughly wetting the accumulation and carefully peeling it away with a wooden or rubber spatula. If the ▇▇▇▇ does not easily come away, or if any evidence of stone damage is noted, do not attempt further removal. c. Lichens grow beneath the surface of stone monuments and are extremely difficult to remove without damage to the underlying stone. If lichen removal is desirable the Department strongly recommends working with a conservation professional to prevent damage.