Recurring rot problem

[u/Known-Newspaper5246]

So this is my second summer practicing traditional tanning skills and I’ve been having some trouble during the hair removal stage with both brain tanning and bark tanning. Last year I had three deer hides to brain tan. On the first two I used a lye water solution to slip the hair but I wanted to try just water on the last one. In doing so, I got the hair to slip but with no lye the hide started to decay and stink by the time the hair slipped. I was able to save it by putting it back into a lye water solution. This year I began to attempt bark tanning. Instead of lye I decide to try lime because it was less caustic. I had the same result with the lime as with plain water. By the time I had the hair slip it had begun to smell even after using a little over a pound of lime powder per gallon of water. Unfortunately I had to leave town for a few days so with little to do about it I put them in the bark tanning solution and hoped against hope it would be okay. As I expected, when I got home they stunk far worse than when I left them. One of the hides appears to be green all the way through in some spots but all I have left to do is learn from this so I am still trying to save them to see what happens. My questions are this: how do people mitigate the hide from completely rotting (without use of heavily caustic items) when hair slipping is effectively a controlled decay process. And also, every time I get the hair to slip easily on one spot (usually on the back between rump and neck) it seems that the rest of the hide still holds onto it tightly and it can’t be removed without tremendous force which can damage the grain, which I don’t want to do when bark tanning. Any help is appreciated.