If you have the time ....
55 gallon drum
put the body in,
add live meal worms and cover
{wait like 30 days}
When the flesh is gone, place the drum on top of cement blocks formed in an "H"
put charcoal in on on side of the open H
keep a low fire going for a day or two to dry out the drum
stir contents of drum with an iron bar (5/8" rebar or pipe)
drill air holes into the drum
add a bucket of coal to the contents of the drum and burn a second time
after the coal starts to burn down, add some chunks of wood
wait till cool
pulverize into dust
till the dust into your garden
cut up drum into metal sheets
dispose of metal sheets, iron bar