It totally makes sense that just having the foam sit for a few minutes will do good. But are you guys saying you should rinse off the foam first and then use a wash mitt in a bucket solution, or just use a mitt in a bucket solution while the foam is still on there BEFORE you rinse it off?Its all about lubricity,,,even with a hose only and no pressure washer its better to form if you can. There is not as much foam without a pressure washer but it can be done . Foaming is better than no foaming because the foam will somewhat loosen and lube the surface to make those bigger sand and dirt particles fall off the vehicle after sitting and a rinse off before rubbing it with a wash mitt. IMO