you could probably do an acid/base extraction, if you have any experience with organic chemistry. freebase mdma is an oil, so it should be rather easy to seperate from the binders/fillers in the pill.
if you have no idea on how an a/b extract is done, i'm sure the information is somewhere on erowid (try looking in the dmt or chemistry sections), and you could use pihkal as a reference for the conversion from mdma freebase to mdma hcl.
i think its too much effort, really. i remember once i tried using various solvents i just happened to have lying around the house {acetone (cuz my mom likes having undiluted nail polish remover around) isopropyl alcohol (c'mon who doesnt have any of that in their medicine cabinent), and ethyl alcohol (everclear or vodka, but vodka has too much water to be really useful...)} to wash out all the unwanted garbage, but i didnt have any activated charcoal (to remove colors and other impurities, and i was too lazy to go to the pet store to pick some up) and i didnt have a proper solvent for recrystalization, so it didnt really work too well...