"A builder in Brazil told me that he did the same, only used a solvent to dissolve the styrofoam. I don't remember what it was, though."
Just about any solvent except Alcohol will desolve it...Gasoline, Laquer Thinner, Acetone, Toluene, Mineral Spirits... I would test to see which one does it with the least clean up problems and one that is less flamable/explosive. I am glad I scrapped mine out...it was very clean and I didn't have to deal with a bucket full of toxic waste.
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