I recently had the same issue, so I decided to use what was in my shop and see which worked best. I tried MEK, acetone, laquer thinner, mineral spirits and xylene. The MEK worked best, but I had to let it sit in a sealed glass jar for a few hours. I had no luck with the other solvents. I've read that nitrate dope thinner is the same as Ironex, but I've never tried it. Use face and lung protection. Nasty stuff!!

Paul