| 1. | Do not clean if stability of stone is questionable. |
 | -flaking face or lettering |
| -significant fractures |
| -grainy surface that readily falls away |
| -any condition that indicates stone is delicate, brittle, or otherwise vulnerable |
| 2. | Do not clean marble, sandstone, or slate stones frequently (once every |
| 10 years is frequent enough) |
| 3. | It is not necessary to clean simply due to fungi, algae, and/or lichens. |
| 4. | Use a soft-bristled brush with natural or plastic bristles. Never use a wire brush |
| or any metal object for cleaning. |
| 5. | Remove loose dry materials with a soft-bristled brush. |
| 6. | Use lots of natural clear water. |
| 7. | Use more natural clear water. |
| 8. | Do not use a sandblaster. |
| 9. | Do not use water pressurized more than 30 pounds per square inch on |
| marble, sandstone, or slate stones. Do not use more than 65 pounds per square inch on granite |
| |
| 10. | Clean from the bottom up to avoid streaking. |
| 11. | Do not use cleaning solutions unless absolutely necessary and then use |
| lots of water. |
| 12. | Follow instructions and precautions on cleaning solution labels. Avoid inhaling, |
| ingesting, and contact with skin. |
| 13. | Always work upwind during cleaning operations. |
| 14. | Use personal protective equipment such as chemical-aprons and shoes; |
| and goggles or face shields as recommended. |
| 15. | Cleaning solutions should be: |
| -biodegradable |
| -Non ionic, non corrosive, non flammable |
| -non abrasive |
| -colorless, odorless |
| -hard water tolerant |
| -non staining |
| 16. | Household ammonia can be used mixed one cup per gallon of water, |
| however, it is often not effective. |
| 17. | Chlorine bleach is not recommended. If using chlorine bleach, use a weak solution, never stronger than 50/50 |
| with water. Rinse immediately with |
| lots of natural clear water. Use vinegar to neutralize. |
| 18. | Do not use any solution which has not been approved for historically sensitive |
| stones. |
| 19. | After using each cleaning agent, rinse thoroughly with lots of natural clear water. Never allow cleaning solutions |
| to dry on stone prior to removing it. |
| |
| 20. | Do not attempt to remove deep-set stains which remain after cleaning. |
| 21. | Do not use protective coatings that are impermeable to water vapor. |
| 22. | Do not repeat cleaning for at least 10 years. |
| 23. | Report any damage immediately to the Department of Cemeteries. |
| |