It's been awhile but I thought I would share this. I finally had enough of my disintegrating acoustic foam and the mess so I started the process today. First I pulled off what I could and both speakers retained about 95% of the adhesive used to attach the foam. I wanted to be careful with the painted MDF so I started with a heat gun on low and a credit card and that just spread the adhesive around. next was goo gone, WD40, acetone, alcohol, olive oil, and even some professional wax remover for repainting cars. None of them really worked so in the end and against my better judgement I'm going to adhere the new foam over old residue since it seems to be drying to a hard consistency. I thought I would post this to save some other poor soul from my frustration and the temptation of using a razor blade on it (don't try).