Sorry you have to deal with this crap, but don't give up too soon if you have the time to fiddle with it. The idea is, the methaqualone.hcl won't dissolve in acetone, while the crap will. Methaqualone the base will dissolve in acetone. So the crystalization relys on the mtq dissolving into the acetone and the HCl hunting it down and binding to form the .HCl and dropping out of solution. Then just filter it and clean it up.
Well, you tried that and it didn't work so drying everything out and trying again is a good idea --- you tried that and it didn't work. The methanol is a baaaad idea. Methanol will dissolve everything and keep it. One would have to evap down to dry AGAIN and go at it with acetone. Don't rinse with acetone! Like I said, acetone will dissolve the mtq base and take it away.
May I suggest you do the acetone trick one more time? Dry the crap as dry as you can get it, it'll probably still be a sticky purple mess. Now add acetone and heat to dissolve as much of it as you can and filter, saving the solids. Set the acetoneandcrap aside for other tests. Now take a look at the filtrate, is it a slightly purple microcrystaline solid? If so, evaporate the acetone and take a look at the dry solid. Is it sticky (it shouldn't be) still tiny, tiny crystals? If so, you may well have succeeded!! Take the solid and do the acetone thing again. Try to dissolve the solid in acetone, if it doesn't, filter and keep it. If it's what you're seeking it will get cleaner and less purple. Now go to the end of the write up I did and do the acidic water clean up and have fun.
Sometimes recognizing success is hard to do, so test it and see what happens.
It may be that the slurry you saw before adding the methanol was what you wanted. Remember that mtq.hcl won't dissolve in acetone. It could be that the slurry is exactly what you're going after.