1. Remember to always test the product on an inconspicuous area first.
2. Liberally spray over the required area and wait 3-4 minutes for the cleaner to react with any iron contaminants. If iron contaminants are found then the cleaner will turn purple and begin to bleed out.
3. Do not allow the product to dry on the surface. Once turned purple, rinse thoroughly with a pressure washer. Repeat steps 1 and 2 if you think further de-contamination may be necessary.