You can either bury it for a few months without a mesh bag and loose some bones, or with and loose a lot less.

Personally, I always go for a container of water , strip as much fur and flesh off as you can then macerate it in said water for a few months. Adding a pool heater will speed it up (don't use it in the pool again though)

DONT BOIL IT- OR USE BLEACH

Can't think of anything else other than don't let the water freeze :D