How do you make your pickle?
How do you wash the hide?
What kind of hide?
How do you salt?
How do you re-hydrate?
Here's my current procedure on these deer hides, based on my limited knowledge.
1. Wash hide after skinning using pressure washer (with no heat). I just do a quick wash to get any congealing blood off around bullet holes and if necessary I'll scrape the blood off with a butcher knife. Of course any meat should already have been removed.
2. Salt hide until butchering is done and I have time to tan. Salt is rubbed into the hide with the hide laid out flat. It usually gets pretty dry and a a bit stiff.
3. Clean all flesh from the hide. I've been simply knocking the dried salt off the hide before scraping with a knife while moistening the hide with a bit of water to help make fleshing easier. I've concluded now that it would be much better to rehydrate the hide and do a proper scraping but I doubt this has anything to do with the pickling solution turning dirty.
4. Pickle the hide in a tub with 1lb salt and 1oz. oxalic acid per gallon of water to a ph of 2.
5. About a day into pickling, re-flesh the hide a final time. I had thought I was doing a fine job before hand but this time I tried laying it over a 6" pipe and using my butcher knife as a scaper which seems to have gotten any remaining tendon layers off the hide whereas before when doing it in its dry state I was always getting an almost never-ending amount of flakes of tendon layers peeling from the skin. Next time I'll try re-hydrating and fleshing properly before pickling.
6. After 72 hours of pickling is the standard rinse, degreasing, neutralizing and then tanning.
So my best guess is that the dirt is coming from the fur side of the hide which I make no special effort to wash. I'm just hoping this won't affect the pickling and if it is then would it be best to mix a fresh pickling solution or will that mess something up for me?