My experience with a heat gun was that it works fine on the painted wood, but the mylar took off the decals over the inserts. In my case this was ok, because I had new ones (Diner). These decals were the main reason I was removing the mylar - a previous owner had done a terrible job. I’m not sure insert decals are available for all games, though. I also like alcohol for removing glue - it’s not as toxic as some of the other alternatives.

I like the idea with the paper towel and the toothbrush (and a plastic scraper - I used one from the kitchen). And I agree, using flour was an an unpleasant mess. What’s the product in step 5 - is that a tenside based cleaner ?