You should do a maceration, no boiling, no beetles. All you need is an aquarium heater and a bucket. All animal tissue liquefies @90deg. in just a matter of a couple of weeks. Boiling tends to make bone brittle as well as bleach will make it brittle.....I've already been down that road.
Water in bucket, submerge skull w/rack left out, keep at 90deg. with aquarium heater and let nature do it's work. Keeping the water at a constant 90deg allows bacteria to grow and eat the tissue...even the brains. Change water every few days and do your best to stay up wind of it or you'll gag.
When done rinse off well with a garden hose, and then soak the skull in peroxide for a few days rinse again and let dry.
Here's a good read and it explains several different skull cleaning processes in detail.
http://ag.arizona.edu/pubs/natresources/az1144.pdf