>>511428185I've been thinking about this, and a blender is really too small to do the job properly.
What you need is a "ball mill". Basically, a concrete mixer + some large ball bearings, or even just bits of metal and stone. You can get electric cement mixers that are big enough to stuff a corpse into. Needs a lid obviously.
Run it for a few days, maybe a week and you'll be left with just a slurry you can pour down the drain.