IPA is Isopropyl Alcohol and people use it to strip off any 'substance' after they do their correction and polishing steps to inspect to see if they have in fact remove the defects an not merely filled them in. I do this sometimes for my Test Spots but once I'm confident my choice of products, pads and process is getting the job done I don't continue to chemically strip the paint.
Here's a great example of why I don't need to chemically strip the entire car to see if I know what I'm doing.
1-Step versus 3-Step Process by Hand
Other thing you can try for cleaning wax residue/dried compound,polish from exterior trim is peanut butter....believe me is a good cleaner, look on that on the forum and you will also find a lot of good information.
It's actually the vegetable oil in the peanut butter, not the peanut part of the peanut butter that dissolves some polish/wax/compound residue. Have some stiff nylon brushes on had of different designs to help agitate dried residue. It's never going to be easy removing the other guy's splatter.
This is why many detailer will take the extra step to tape off rubber and plastic components just to avoid having to remove splatter that lands on these components by accident.
This is called, TOGW or The Other Guy's Wax
Here's a tip...
One of the thing I do before taking a job is to inspect the car for the other guy's wax in the cracks, often times this will be from the owner of the car that you're standing there talking to.
Look around any components, especially if they have a gasket under them or a seem with plastic, vinyl or rubber trim. If there's a sunroof, look around the gap for the rubber or fuzzy seal to be creamed-out with polish or wax.
If you find this kind of shoddy work, be sure to take a few pictures of it and also point ti out to the owner so he knows you know it's there before you even start to work on the car.
Then let them know that you're willing to try to remove the other guy's polish and wax splatter as a part of the job but let them know HOW DIFFICULT and TIME CONSUMING it is and that you can't make any promises that you can get it all off because it's so difficult and time consuming.
IF the person you're talking to is the person that normally waxes the car at a minimum it will bring attention to the fact that in the future they should be more careful and hopefully they'll appreciate your attention to detail as well as figure out you actually do know what you're talking about.
Also, while you're looking for wax in the cracks, take a look for any places some other guy may have burnt the paint off of high points and corners and point this out to the owner BEFORE you work on the car.
This is where an inspection form comes in handy so you can mark any pre-existing problems, point them out to the owner and protect yourself from getting the blame for someone else's mistakes.
