I used to use beetles, but had to sell the because I moved. So I now skin the head, cut as much meat as possible. The wrap the bases of the antlers up so they won't darken when boiling. I then boil the skull. I scrap off meat about every half hour. When the skull is clean, make sure the skull has all the teeth yet. I then whiten the skull with 40% peroxide and powdered bleach (both from a beauty salon). I mix them together to a toothpaste consistancy then apply it to the skull. I wrap up the skull and leave sit for about 3 days. I then rinse off the skull and attach it to the plaque. If the skull isn't dark enough, whiten again.
Here are some I did last year. Obviously the ones in front are done and ones in the back are in the process. Here is also a coyote.