SOAK means SOAK. Sometimes time helps, and you have to give a solvent some time to work. Just increasing the heat doesn't mean it will obtain the desired effect in less time. I always found a soak worked best to remove povidone, for instance. A boil didn't do the same trick, but a four to six hour soak in the same solvent would get the povidone.
Take your time. Your haste might be counterproductive here.