Hello, in this video we’re going to try and cover the basic procedures for cleaning a stone grave marker. The first and most important thing to remember is to do no harm. While stone seems to be a durable material. It can be affected by weather and pollution. These are delicate structures and a great amount of care must be exercised when cleaning them.
Now, before we get started, let’s briefly go over what not to do. We don’t want to do anything that will remove or damage the original surface of the stone. We never recommend the use of bleach or other salt laden cleaners. It is also never advisable to use any strong acids or bases.
Finally, we don’t want to use any harsh mechanical devices such as sand blasting, high pressured power washers, or power tools such as sanders or drills equipped with a wire brush. All of these methods can damage the grave marker. Let’s look at some damage that has resulted from well intentioned cleaning with poor cleaning techniques.
Ok, so now that we know what to avoid, let’s get started and set down the ground rules for how we’ll proceed.
In keeping with our “does no harm” policy,” it’s important to select the gentlest cleaning method possible to accomplish the task.
The first thing we need to do is to select our tools before we proceed with the cleaning instructions. Always locate your nearest water supply; it takes a lot of water to properly clean stone. If your cemetery does not have running water then it is important to bring barreled or bucketed water to the site with you. Also, it is good to have your selected cleaner in a convenient spray bottle. As for the brushes you always want to use soft bristle ether natural or synthetic. The general guideline is that if your brush is safe for cleaning the hood of your car that it will work well for historic stone.
For chemical cleaning, acceptable products are detergents, solvents, surfactants, biocides, and intermittent water misting. When looking for the right type of cleaning product to use, try to find a non-ionic detergent or a product containing biocide with either a neutral pH or a pH similar to that of the stone. We can learn more about the cleaners by reading the product literature and the materials data safety sheets.
All right so lets get started. In keeping with our “does no harm” policy, we’re going to want to make small tests to make sure we’re not going to damage the stone.
We have evaluated the selected cleaners and we like the properties of this particular one for this stone. There doesn’t appear to be any damaged caused by the cleaner and the appearance is satisfactory, so we’re good to continue.
Now we’re going to want to soak the stone before we begin. Stone is very porous and will quickly absorb any cleaner that is applied to it. By soaking the stone first it allows the cleaner to stay on the surface on the stone. This minimizes the impact to the stone and maximizes the cleaner’s effects.
Once it’s wet, we start cleaning from the bottom and slowly work our way up. Starting from the bottom of the stone minimizes streaking. We’re going to want to use small circular motions as we go; this helps to get into all of the crevices. Sometimes it is important to switch brushes to meet the situation.
Also, as we said before, we’re going to want to use lots of water.
And there we have it.
We’ve gone over the basic cleaning methods that will work with a variety of stones. These procedures are not only useful for general cleaning but can also be performed before more complicated repairs or conservation work. Good luck.