Headstones are constantly exposed to the elements and can develop hard water deposits from rainwater. Hard water has high concentrations of dissolved calcium and magnesium which, over time, can create a hazy film on the stone's surface. With the use of gentle cleansers, these deposits can be cleaned, improving the stone's appearance.
Hard water can be removed from headstones with the help of non-ionic cleansers, which do not react with the minerals in hard water deposits. These cleaners can be purchased from janitorial, photographic and conservation supply companies. Fresh water, such as spring water, should be used with one part cleaning solution to five gallons of water. Acidic cleaners or products used to remove household hard water stains should not be used to clean a headstone. They can irreversibly damage the stone.
Preservationists recommend natural bristle brushes for cleaning headstones. Wire brushes are damaging. Toothbrushes and non-metallic scouring pads can also be used.
If the headstone shows cracking or flaking, cleaning the stone may cause more damage. Fragile stones may require professional cleaning. Additionally, pressure washing is unwise because it not only chips headstones made of softer material but strips paint from inside engravings.
- head stone 2 image by PeteG from Fotolia.com