Cleaning Headstones Using Biological Cleaners

Over time, headstones will accumulate algae and mold. In the past, our cemetery used careful scrubbing to remove the algae and mold. Now we use the D/2 cleaning solution.  This is much more effective than mechanical cleaning and it does not put any wear on the headstone. Another plus is that these cleaners can stay effective for two years or more. See the photos below.

Here is a link to the National Park Service's report, Best Practice Recommendations for Cleaning Government Issued Headstones

Here is what the National Park Service says:
Biocidal cleaners are available for use on stones that have biological growth, such as algae, mildew, moss, and lichen. Most biocidal additives also help to keep biological from returning to the stone for an extended period of time. Recommended biocidal cleaners include D/2 Biological Solution manufactured by D/2 Biological Solution Inc.,2 Enviro Klean® BioWash®, Wet & Forget® or other cleaners that contain quaternary ammonium compounds. Consult with the product manufacturer to determine if the biocidal cleaner contains buffers that may leave salts behind on the stone. Follow directions as specified by the biocide manufacturer, making sure to rinse thoroughly. It is important to know that marble cleaned with biocides should continue to lighten over the next few days. The advantage of a biocidal cleaner is that it helps remove a wide range of soiling including biological growth.