Same process. Any kind of emulsifiable oils work-brains, eggs, a mixture of soap and pure neatsfoot oil, etc. I think brains work a bit better than eggs, maybe, but I've tanned one deer hide with eggs and it came out pretty good. Make sure you wet the hide, wring it out thoroughly, and stretch it good in all directions before you put it in the eggs so that it's opened up and will soak them up. You may have to apply them more than once to get complete saturation of the hide.