Fatman pretty much summed it up. I've dried complete deer hides with salt and borax. Both work.

-If you use salt, you'll need to replace the salt once it's all wet and feels like wet sand (every couple days at first). Scrape off the wet salt and let the wet salt dry out in another place and put fresh salt on the tail. You can re-use the salt this way.

-If you use borax, borax doesn't seem to adsorb the moisture like salt, but will dry the raw hide just fine. Where the moisture goes is still a mystery. Borax seems less messy because of this, but salt is much cheaper. Both work. An oscillating fan in the area to keep the air moving around it will help some too. The main factor that will determine how long it takes is the relative humidity. The first deer hide I did (with salt) was in an unheated garage in early December, the weather stayed above freezing and rainy for the first couple of weeks. Obviously wet things take much longer to dry out in these conditions.

The only difference I have with Fatman's method is that I wont use Dawn or any other 'detergent' on hair. I only use shampoo and conditioner. My feeling is if you wont wash your own hair in it, you shouldn't use it on natural material like this. For those that say say Dawn is safe, I say use it on your own hair and see how your hairs feels afterward. If you're unwilling to use Dawn in your shower what does that tell you about how harsh it really is. I still say if Dawn will dissolve crude oil, what do you think it does to the natural oils in hair? In living animals natural oil is replenished through the body. In harvested animal hides, any natural oil lost in the cleaning process will never be replaced, and using oil dissolving detergents just makes it worse.

I know, I know, there are many people that have been using Dawn for years and never had any problems, but if that's the only way you've been doing it then you don't know how much softer the hair would have been by using shampoo instead.