Acetone will work on the monokote, but don't get it near the canopy.. you'll have a mess. A few years back, I noticed that the industrial 'de-bonder' that we used had a main ingredient listed... Nitro-methane! Yep, same stuff in 10, 15, 20% in our fuel. Try some Hi-test fuel on a paper towel, it might do the trick.

good luck.