Gravestone Cleaning & Repair
The biggest thing to remember here is that many gravestones are far more fragile than you might think. Primary importance should be placed on preserving the stone in readable condition for years, even centuries, yet to come. Time and erosion create subtle but continual damage. Do nothing to hasten that damage.
Steps:
- Test clean a small area in an inconspicuous place to make sure the result is what you are after.
- With a soft-bristled brush such as a nylon brush, remove loose dry materials.
- Wet the stone thoroughly with clear water.
- Scrub with soft brush and plain water (Never use a wire brush, Brillo pad, Scotchbrite pads, steel wool, sand paper, or such material).
- Clean the stone from bottom up to avoid streaking.
- Make sure the stone is wet before applying any cleaning solution (see recommended cleaning solutions later on this page). Try the mildest cleaning solution first.
- After using cleaner, flood the stone again with clean water and scrub. Do not let any cleaner dry on the stone before removing it.
- To clean details of lettering or designs: On granite or slate, use a soft wooden stick like a tongue depressor or ice-cream stick. Never use a metal tool. On softer, grainier stone such as sandstone or limestone, be more careful. Use a soft toothbrush or cotton swab.
- Finally, thoroughly rinse the stone with lots of water.
- (Remember that marble stones are far softer and easily broken than might first appear.)
Procedures to avoid:
- Avoid acidic cleaners on marble or limestone.
- Avoid sandblasting stones.
- Avoid high-pressure spraying.
- Do not attempt to clean any stone that is unstable.
- Do not attempt to clean stones without receiving proper direction.
- Never use wire brushes or any metal instrument in cleaning stone.
- Do not substitute household cleaners for those listed here.
- Do not clean stones often. Even the most carefully cleaned stone loses stone particles with each cleaning.
- Do not plan to clean stones more often than once every several years or longer.
- Avoid treating stones with “protective” coatings that are impermeable to water vapor. Such coatings can actually be very harmful to stones over time, and other are ineffective.
- Do not use household cleaners such as Ivory soap, detergents (liquid or powder), Borax, Clorox, TSP, Calgon, Fantastik, Formula 409, Spic & Span, or any abrasive cleaner.
Tools for stone cleaning:
- Goggles
- Rubber gloves
- Tampico (natural bristle) or plastic scrub brushes
- Toothbrushes
- Sponges
- Assorted brushes (not wire)
- Smooth wooden sticks such as ice-cream sticks or tongue depressors
- Cotton swabs such as Q-Tips
- Spray bottles
- Plentiful supply of clean water (a hose if helpful)
Recommended cleaning solutions (listed in order of increasing strength):
Note: Always use the weakest cleaning agent that cleans the stone effectively. Use only those solutions recommended for the type stone being cleaned.
Marble and Limestone
- Water only.
- Non-ionic detergent, such as Photo-Flo (available from photographic supply houses).
- Triton-X 100 or Igepal (available from conservator’s supply houses), and water. Use one ounce to five gallons of water. (Triton-X 100 is also available from the Local History Office of the Kentucky Historical Society).
- Vulpex (a soap appropriate for stone cleaning available from conservators’ supply houses) and water. Use one ounce to five gallons of water.
- Household ammonia. Use one cup to one gallon of water.
- Calcium hypochlorite. Use only to remove biological growth. Available as HTH and other swimming pool disinfectants. Use one pound dry to four gallons of water. Must be dissolved in warm water.
Soapstone
- Water only. Very fragile to erosion.
Slate
- Water only.
- Non-ionic detergent and water (see Marble)
Sandstone
- Water only.
- Non-ionic detergent and water (see Marble)
