You might have better luck with a a mixture of acetone and absolute ethanol. I don't have a clue as to what the pyrolysis products are, but some might be a little polar and absolute ethanol is a great solvent for such things. Just a little water (5%) changes the solvent potency of ethanol greatly. Absolute will dissolve fat; 95% is much less effective.
In short, try acetone. If that doesn't work (I suspect it may not), change to 50% to 75% ethanol (absolute or denatured) in acetone. My usual elixir for removing excess flux is that mixture (i.e, 75% absolute ethanol, 25% acetone). Isopropyl alcohol may work as a substitute for the ethanol. I just happen to have a lot of ethanol on hand.
John