Thanks,I appreciate the opininions.
1: reason I do not contact the "perpetrator" first is that in my experience I often get less than the truth when I surface with problems.Usually I get "explanations" and often distortions.So I like to get outside opinions first.

2:I just did contact the taxidermist with the story.
He tells me that the skin is degreased and tanned.Fat has been taken out with soap not organic solvent.
He also uses an "acid" other than carbolic acid which he no longer uses..He thinks its this "acid" that I am smelling- not rancid fat.He recommends airing the beast out.

I get the acrid smell only at warm temperatures.To me that means I have to wait for summer when we have 90-110 deg winds here.My home is 72-75 deg,enough to stink,but prob not enough to get the phenol he calls acid out.

Taxidermist hopefully know what I am talking about

thanks again

sheephunter

Sheephunter
Soap alone will not degrease the bear hide.
Before the tan,the hide goes into a pickle bath(that's the acid),after being shaven(skin is made thinner)and being degreased the skin goes back into the pickle so the acid will penetrate all the way,take out of pickle,drain and then as to be neutralised,rinsed and then put into tanning solution,take out,rinse and then is oiled.
If the rug stinks,I doubt highly that it is the acid,no mount or rug should smell from the acid used.
If the rug has a felt backing you can do a small test,cut the thread that secures the rug to the felt(an inch or two)then look on the inside of the hide(leather side)should be white to light tan,if its yellow you have problems,scrape the inside to see if you get anything,you should get nothing when scraping.Also smell it,you know a rancid rotten smell when you smell it.
AGAIN,freeze it,if it was tanned properly but not degreased,the all process can be redone but of course it has to be watched very carefully.
Your taxidermist should take the rug and fix it butI doubt he knows how from what you said.
I wish I could give you an easy fix.FREEZE IT.
Talk to some local taxidermists(to you) and listen to what they tell you.