Raptorazor and a cordless drill for the brain cavity. Turns EVERTHING into a milkshake that pours right out when you add a little water. Even have shown it to multiple Fish and Game folks and all have given it the thumbs up.
Coat hanger works well for the brain removal. Eyeballs are easy.
I'm all for leaving the spinal cord and brain to meet the regs but if your animal tests positive you probably brought prions home regardless of the de-brain method. Prion disinfection is a rabbit hole that G&F regs just haven't solved. Whether it needs to be solved is a whole other discussion.
Shoot does and cows. Leave the head and spine in the field.