Ex owner/operator of custom body/paint shops:
In the past, I've had to remove all sorts of different finishes and topcoats from all different types of things..
For the most part, topcoats are pretty durable, and will require either physical sanding/removal,
or, a really good gel/liquid stripper to help break them down..
Alcohol is very mild, so usually only good for 'cleaning'.
Acetone - A good choice, as it is more destructive to a lot of topcoats..
The Usual 'Paint Stripper' [Many brands] gel/liquid chemical/organic:
They all tend to be hit-and-miss.
Klean-Strip Aircraft Remover - This stuff works AMAZINGLY.
It comes in a few different sizes, and was all I/we ever used. It was that efficient on everything.
It's a bit 'hazardous' as far as fumes and skin contact are concerned, so glove up and ventilate..
Base materials I've used it on: Fiberglass, Metals, Woods. [It did not harm any of them]
Do Not get any of this stuff on Plastics/Rubbers. Not all, but some plastics/rubbers will break down/melt.
Paint it on thick and let it do it's thing. I usually wait 10 min or so..
The topcoat will eventually break down, bubble up, and become a mushy mess..
It can then be scraped / wiped away.. Repeat if/when needed.
When done, thoroughly clean the object/surface off with soapy water. I use Dawn liquid soap..
Hope that helps a bit.

Sam -