I use simoniz foam additive in my presoak, bug off and foaming tire brush. I use 1/2 ounce per gallon of bug off and tire cleaner and an ounce per gallon for presoak. It does add to the visual effect, reduces spitting on the foaming tire brush and helps the presoak and bog off hang on the car longer. https://www.kleen-ritecorp.com/p-9290-simoniz-f1170-foam-additive-1-gallon.aspx