Tonight a buddy and I were skinning a red and just above the hind quarters (belly side) the skin had a grennish tint to it. I have seen gangreen before and don't think that what it is. There were no injuries anywhere on the fox. It was caught yesterday but its been cold enough to let hang. Anybody have any ideas? Wish I took a pic.

Yeah, just a little taint, after you skin it, rub some borax on that greenish tint stuff, to stop the tainting.

Quicker than Borax is to sprizt the area with a bleach mix, couple of cap fulls to a cup of water in a spray bottle.

It will stop it cold on contact, as well as take the smell away.

Sooo....is the pelt ruined? or just a lower grade pelt I know that "greening up" stinks to high heaven....

Also hang fox by thier hind legs if you can't skin soon after dispatch. The guts move higher into the body cavity and slow the taint.

Use the water/bleach method.
I had a hide with green belly that I tried to stop with borax.
It graded out as 'damaged' from the auction.
I had another I treated with water/bleach and it graded out with no damage. The water and bleach will stop it and kill it. The borax gets into the skin, and no matter how good you try to wash it, it will come to the surface once it dries.

IMO the hide you describe is not ruined or down graded, a "little" green is normal and/or expected on fox.

If you cant hang the fox as Stewie suggested, be sure to transport and store them on their backs w/ head downhill when poss. Its all about keeping the corrosive guts away from the thin belly skin till you can get the critter skinned. Fox and rats always get done first in my shop then mink,coon and beaver are always last.I do not trap any coyotes or cats but I would assume they should be handled as the fox and rats are.

Good Luck!!