Review on Orvus WA Paste Cleaner 120Oz by Keith Norred

I use Orvus to remove black stains from flat headstones. These stains are the result of tree sap, algae, mold, and dirt that have mixed together over the years, creating some sort of nasty mix that's difficult to remove. Orvus needs to be diluted as it is thick and "runny". I mix two tablespoons of Orvus with a liter of water and apply through a spray bottle. Wetting the stone with water helps reduce surface tension. A good coverage of the Orvus marker and a subsequent waiting time of 15-20 minutes allow the product to harden. The stone needs to be sprayed with water and brushed vigorously, but usually just with a nylon brush. Don't use metal on stone. This usually involves doing this process twice and then rinsing thoroughly. It is not a biocide and will not kill mold or biological growth like D2, but will help remove stains. Needs some elbow grease.