Never going to pay for a euro again after doing several myself. I feel like I got my process dialed-in this year (did 3)
1. Cut as much meat off of the skull as possible.
2. Boil with dawn soap and baking soda. Dawn cuts grease and baking soda helps break down tissue. **Note: don't over-boil. I made this mistake and the delicate bones get really brittle**
3. Periodically check the skull while boiling. Power wash as you see fit. The greatest benefit of the power washer, in my opinion, is being able to blow the brain matter out. Just aim the washer in the spinal cavity and it should blow everything out clean.
4. Once its clean, let the skull dry completely (maybe overnight - depends on humidity).
5. Use 40v peroxide developer for whitening. The cream is easier to work with than the liquid. **Note: protect the bottom of the antlers or you'll whiten them too**
6. Wash the developer off and apply more coats if necessary.
As they say, there's more than one way to skin a cat, but this worked very well for me. Takes some time, but it's not very labor intensive.
Here's the whitener I use: 40v Peroxide Developer