Add Siding GRIP powder to the cleaning solution
Wait 10 minutes for thickening to complete.
then add Siding GRIP and reapply cleaner to stubborn areas.
(This approach allows just 1 Siding Grip to be used / 1000 sq ft cleaned.)
After adding Siding Grip to the Siding OX 2000 on the cleaner stayed on the siding even longer and it was easier to rinse