Here is what to do with it. Check and see if it is oily or still hs raw meat on it. If so it will need to be scraped and dried out again. If not then a real good bath will do the trick. I would suggest soaking it for several hours in hot soapy water. Then rinse it out real well and peg it out and dry it. Then put it in a bag with some ceder chips and that should make it smell much better.
If it has greese and meat left on the skin it may not be worth the trouble of trying to save it. I have thrown out more than one in my day. People think they are doing you a favore and stick the tail or hide in a plastic bag and give it to you 2 months later. If that is the case just get ride on it. They just don't cost that much to make it worth your while.But thank the person anyway. Ron