I have a friend's bear hide to flesh for tanning. He put the bear on the back of his jeep in a receiver hitch rack. The dirt roads were wet and the hide got covered in road dirt and small stones. The hide also has birdox burrs in it. My question is how, is the best way to remove these things from the hide. If i need to wash before fleshing what soap do you recommend like dawn dish soap or some kind of no tangle shampoo?
If I wash the hide do I let It dry before fleshing? Thanks for any help.

I'd use a good conditioner and avoid soap or shampoo. Then comb it out.

Horse mane and tail, oughta both clean and detangle, Pretty much any tack shop should have it.

This^^^

I would recommend washing after fleshing. I always just use dawn dish soap then rinse thoroughly,then let it drip dry. You can use an old towel later to help remove any excess water.

What about the stones and burrs? If you try to flesh it before removing these, they can cause you to cut the hide while fleshing.

Stones and burs should be on the outside of the hide unless he transport the hide with it flesh side out.

I see your point scout20 if your using a fleshing knife I always used a wire wheel to flesh.

They create a lump and those are cut off when fleshing just like lumps of fat and meat.

Tractor Supply carries it too.

If you flesh it on a beam before removing the grit and burrs you will cut a lot of holes in the skin, if you wash it first it will be slippery and slimy and hard to flesh on a beam. I first would flesh off the thick stuff by hand with a knife, then salt for a few days, then wash with a non or low alkaline detergent then flesh as well as you can on a beam. The salt will firm-up the skin making it easier to flesh when slimy.

Then either put directly into pickle bath, or hang the skin to dry for a day then re-salt for a couple of days.

All good advice above, he did create a ton of work to comb clean, wash, and take care of it so you or the tannery don't cut gobs of holes in the hide when it's fleshed and shaved, (if the tannery does that).

I would just flesh it over my knee with a large curved skinning knife(easier than doing it on a beam in any case),then stretch and dry as normal.
Then when the hide is dry the sand and dirt can easily be shaken and blown out of the fur with an air compressor.
The burrs,if not tight in the underfur will come out at the tanner.

Skin the feet and head. Lay it out over a fence or beam (drainage) and hose it down/shampoo to get the road grime out. Throw it in the washing machine cold cycle. Adjust hide so spin cycle will work ok making sure fur side is mostly out so water can spin off.. Lay it out on a tarp and get an air compressor or leaf blower and dry the fur and excess water from skin side. Flesh as usual. If you flesh the hide on a beam while full of gravel, burrs and wet clumped fur you'll shred it.
Give stern lecture to friend about garbage bags or game bags for hides on receiver hitch rack so they don't get filthy then charge him double.

OR....

If it's just sandy grit throw it over fence/beam whatever and let the hair dry then work it over good with compressed air/leaf blower. Much less work than washing if it will do the trick.

Thanks guys for all your responses. I guess I should have said the entire bear was on the receiver rack, it had just been shot and was gutted. they didn't have anything with them to rap the bear in to transport it without getting the dirt road splattered on the bear. Thanks again