Headstone cleaning removes biological growth and soiling from grave markers using a conservation-approved biological cleaner and soft brushes, with no pressure at all. Nearly everything people do to headstones themselves — bleach, vinegar, wire brushes, pressure washers — causes irreversible damage to the stone.
What not to do, and why
Well-meant family cleaning is the most common cause of damage to old markers, and every method that gets recommended informally is harmful.
- Bleach — leaves salts inside the stone that crystallise and spall the surface off from within over the following years
- Vinegar and acidic cleaners — dissolve marble and limestone outright. These stones are calcium carbonate; acid is not cleaning them, it is consuming them
- Wire brushes and abrasive pads — scratch the surface and take inscription detail with them
- Pressure washers — old, weathered stone is far softer than it appears and pressure erodes the carved lettering that is the entire point of the marker
The lettering is the thing you are trying to preserve, and it is the first thing every aggressive method destroys.
The correct method
Conservation practice uses a specific approach: clean water, soft natural or nylon brushes, and a non-ionic biological cleaner formulated for historic masonry. The one commonly specified is D/2 Biological Solution, which is what the National Park Service and the Department of Veterans Affairs use on government headstones.
It works slowly and that is the point. The cleaner kills the biological growth and the stone continues to lighten over the following months as weather carries the dead material away. A marker often looks markedly better six months after cleaning than it did the day it was done.
Before anything is applied we assess condition. Stones that are cracked, flaking, delaminating or unstable should not be cleaned at all until they are stabilised, and in those cases we will say so rather than take the job.
What we clean
Individual family markers, upright monuments and obelisks, flat and flush markers, military headstones, and small family plots as a group.
Marble, granite, limestone, sandstone and slate each behave differently and each has its own tolerances. Granite is the most robust; marble and limestone are the most vulnerable to acid; sandstone is the most prone to surface loss.
Bronze plaques on granite bases need a different approach again, and we will discuss that separately if that is what you have.
Cemetery and veterans' work
We are glad to work with cemetery boards, historical societies and veterans' organisations on section-wide projects. Larger groups are quoted at a lower per-marker rate for the obvious reason that the setup is shared.
Before Memorial Day we set aside time for veterans' markers at no charge. There is no complicated reasoning behind it — the stones deserve it and it is the right way for a local business to spend a day.
If you look after a family plot and are not sure whether the stones are stable enough to clean, send photographs. We would rather tell you to leave a marker alone than damage something that cannot be replaced.