pickling is basicly soaking the hide is an acid solution of about 2.5%, some use nicer/ safer acids than others. Think vineagr compared to battey acid, both can be used in the process. Then the hide is neutralized by flushing with water and baking soda. then the hide is broken by stretching as it dries then smoked or rubbed with oils If that doesn't happen then the hair and hide will deteriorate due to the high acid content. . If you find your hide is just pickled you can buy a tanning kit but beware its alot of work and why they are cheaper lol. I tan rabbit hides in this fashion. There are several ways to tan hides or furs, this is just one of them but its used mostly on hair on hides or furs because its a cheap method.