So, you've just finished scraping off the lichen and scrubbing the gravestone with water. Now it's time to apply D/2 Biological Solution to kill the lichen and whiten the stone. You spritz some on the damp gravestone and...oh no! Why is the gravestone turning pink?! Don't worry--sometimes stone will turn a subtle color of pinkish-orange after applying D/2 Biological Solution. The manufacturers of D/2 explained it to me that the color change is the result of the biological organisms reacting to the D/2. This temporary discoloration can take on shades of orange, pink, or gray. Not all stones react this way but some will. When it does, it will generally take 24-48 hours before the discoloration disappears. So, the only downside is that you may have to come back after a few days to take some good "after cleaning" pictures.
Jarrod Roll...museum curator by training, preservation educator by passion. Director of the Monroe County Local History Room & Museum, Sparta, WI. Owner of Save Your Stones Gravestone Restoration Services. Maker of the Gravestone Cleaning Kit.