Hard Waxes (ie Turtle's Super Hard Shell)
I was waxing my civic yesterday night (BMWs in the shop) and I had never used turtle wax's super hard shell wax before. I was in the shade in the evening and I started going at it. The application was just fine. I went over 3 or 4 panels, starting from the driver side door.
However, when I finished the 3 or 4 panels and went to check on the first panel, I realized the wax had become _rock_solid_. It was ridiculously tough to wipe off and after spending about 6-7 minutes of solid buffing 100% strength,I finally got most of it off. I ended up using some of the soap solution, that I had used to wash the car, to soften the wax so that I could take it off.
Do one or two panels at a time people and make sure to wipe it off as soon as it hardens!