Lots of ways to do this and I've tried many of them. I don't salt the hide, I either freeze it green for later, or lash it up and go to work. I typically use the shin bone off a cow as a fleshing tool. File it down and add little teeth. Be sure and get the membrane off the flesh side along with the meat or it will be stiff where you miss it. Somewhat the same with the hair side and the epidermis. Get it all and it will tan better. Assuming you are brain tanning.