1. Determine the composition of the stone, if you're not sure. This article deals specifically with granite, being the hardest and most commonly used materials for headstones it can stand a bit more of an aggressive approach to cleaning. Granite comes in many colours our stone samples page may help in working out if your memorial is granite. If your memorial is a white stone and dates pre 1930's it most likely will be marble.
2. Inspect the stone for any damage, cracks, or flaking. Stones with damaged areas should be washed with care to avoid further damage. Be aware that too much cleaning can remove the polished finish of a stone you should only clean a granite memorial when it is needed.
3. Thoroughly wet the stone to start softening any materials on the stone using a soft brush and a bucket of water. If the stone has rocked surfaces with Lichen or moss add bleach or ammonia to your water this will kill the Lichen and Moss, also be aware this can kill the grass around the base of the memorial. If you are cleaning off Lichen and Moss give it 10-15mins before starting the next step.
4. Start cleaning the polished areas with the flat face of your solve soap block use plenty of water to keep it moving easy after the surface is clean, rinse off all the soap suds so that there are no soapy bubbles on the stone. Now clean off the Lichen or Moss on the rocked areas with a scrubbing brush using plenty of water
5. Avoid any abrasive cleansers that can scratch the stone. Make sure you clean off any cleaners that you use, as many cleaners leave behind stone eroding chemicals that will speed the deterioration of the stone. Stay away from metal wire brushes.
6. Once you feel it is clean give it a wipe dry with a towel and wipe off any soap that may be left on the stone. If there are still spots you've missed give them a spot clean.