I have seen and had good luck using what we called the "bondo buster" DA from Snap on... Some 36 grit and it will go through paint pretty quick.

I watched a bodyman clean up a door jamb with a "finger" cleaner, a type of long fingered wire wheel that made a tough job much simpler..

The fiber disk ( you use on a drill) does a pretty good job also.

I am aware you asked about "chemical" cleaners, but I thought I would give you some options I have seen/used...