On a windy day, skin that thing out. I say windy so that you aren't gagging so much. Then, your options are boil or bury. Bury is easier, dig a hole, put the head in with the antler bases level with the soil. Cover with a bucket or something similar to keep dogs off of it. Wait a couple of months.
If you go the boil route, find a container that you can submerge the head just to the antler bases. Slow boil for a couple of hours, some have luck pressure washing to remove the flesh after the boil.
What you do after getting it clean is up to you.