Stripping paint from models that have been treated with 'Ardcoat

The title says it all, really - I had a run of bad luck with purity seal causing some serious frosting (in retrospect the humidity was too high). Looking online I saw 2 possible solutions (short of strip and redo): respray with purity seal and dry with a hair dryer, or spray with 'Ardcoat. As I had a can of spray 'Ardcoat and don't have a hair dryer, I tried 'Ardcoat, and while it salvaged some of my miniatures, others were made worse. No problem, I thought, I've got simple green, I'll just stip those and redo them. After 3 days of soaking I'm beginning to get alarmed at the lack of progress (even with a toothbrush nothing is shifting on some of the models). Is it just a matter of leaving it longer or do I need something with a bit more oomph if there's 'ardcoat?