The trick to nitromors is that it mustn't dry out. Slop it on your frame, then do another coat, then wrap it up in clingfilm and put it in a cool shady spot (in the shed or something) and leave it for an hour. I've never seen paint that hasn't been removed easily with this method, and I used to be a fabricator/painter/general dogsbody in a film set works, so I did this all the time.
I find that scraping the paint off (e.g. with a plastic spoon) works well, then going over with wire-wool dipped in thinners. For getting it out of the little nooks and crannies, you can get tiny brass wire brushes from automotive tool shops (they're for cleaning out spark plugs). They don't leave big scratches like steel ones. Toothbrushes work okay, just not as well.
The trick to nitromors is that it mustn't dry out. Slop it on your frame, then do another coat, then wrap it up in clingfilm and put it in a cool shady spot (in the shed or something) and leave it for an hour. I've never seen paint that hasn't been removed easily with this method, and I used to be a fabricator/painter/general dogsbody in a film set works, so I did this all the time.
I find that scraping the paint off (e.g. with a plastic spoon) works well, then going over with wire-wool dipped in thinners. For getting it out of the little nooks and crannies, you can get tiny brass wire brushes from automotive tool shops (they're for cleaning out spark plugs). They don't leave big scratches like steel ones. Toothbrushes work okay, just not as well.