As it says on the website, the pre-cleaner is a chemical, not abrasive, cleaner. It "fills in the swirls" and "rounds the edges" so the swirls "seem to disappear." I tried it on my girlfriend's car. She's used the snowbrush on it regularly and has been caught once using the scaper!
("I was careful. I couldn't find the brush and I was in a hurry.") I didn't seem to notice much difference, and I tried different techniques/amounts. I think it may make the swirls seem less noticeable if you don't see a direct light source reflecting off the paint. It did seem to lessen the noticeability of some scuffs though.
I'm definately going to have to do some more work on it than just the hot wax at the car wash!
