It seems like most painters use "Pre-Kleeno" or similar products shortly before painting, which is totally incorrect. Another cleaner called a pre-paint cleaner is what is to be used on paint day. The other one is meant to be used before even sanding the old paint, to remove wax etc as much as possible. Pre-Kleeno can leave an oily residue. Until very recently I had a body shop, I have seen this a lot, usually with decent results, but sometimes it bites back. We are (most of us) guys, who reads the instructions? Not us.