Unless you can turn the pressure way down I wouldnt use a pressure washer. Tried it on a skull last year and busted several of the smaller bones in the nose.
I pressure wash all mine. I just make sure to avoid areas like the nasal cavity. In my opinion there is no better way to remove all the small bits and pieces, especially under the back of skull near the ear canal where all those little crevices are. I'll post mine up soon, plan on whitening this weekend.
My bullet point process on this skull:
- Skin and cut out as much meat as possible, including eyes.
- Screw driver the brain to allow water infiltration a little better.
- Heat with small amount of oxyclean in water. Not boiling, low heat, just want the water steaming, maybe "moving" a little. Do this for a couple of hours.
- Remove, pressure wash loose meat and brains out. Take care to avoid the nasal cavity and antlers
- Place back in hot water with Dawn or Joy soap, and remove to scrape or pressure wash daily until all scraps of meat are gone. This will take another day, maybe 2 if you are lazy.
- Now all the meat is gone, place in hot water with lots of Dawn. Like others have said, 1/2 cup per gallon of water or so. Lots of it.
- Keep this water hot, 90-100 degrees. I use a stock tank heater. Change water out every couple days. Takes about 2 weeks and the skull is degreased.
- Mix basic white and 40 volume peroxide gel. Paint onto skull and wrap in saran wrap. Put under heat lamp if you have it, or direct sun if its warm. Otherwise 24 hours is enough.
- Remove saran wrap, let peroxide dry and then brush off. Rinse thoroughly with hose.
- Apply light coat of Mop n Glo to protect and preserve bone. Doesn't have to be heavy and glossy, won't hardly notice it's there but does preserve the integrity of the bone long term.
- For those that don't want the glistening white skull, you should still use some household peroxide for a couple hours. It will kill off any bacteria still living on/in the skull that will cause it to stink over time. It won't do much to change the appearance, but will keep it from smelling.