You will need
  • milk, dry red wine, vinegar, soy sauce, onion, garlic, spices, herbs.
Mutton meat during cooking smells, to put it mildly, unusual. Getting rid of the smell, you can spoil the taste of the meat. Widespread method of soaking the meat, but some marinades can make it tougher. As a harmless hot or cold marinades you can try red wine or Apple cider vinegar. Good smooth flavors of sheep's milk and soy sauce. Usually meat is marinated during the day, but lamb is better to reduce from a couple hours to almost 30 minutes (depending on the composition of the marinade).
It is interesting that young lambs have little to no odor, in contrast to Mature males. A bad smell exudes not the meat itself, and mutton fat. Before cooking take care to clean the piece of fat. The presence of sharp smell depends on the food. It is better if the animal is from time to time out in the pasture.
If you don't trust pickles and I'm afraid that without the fat the meat is too dry, try to recapture the smell of various spices. Fit sharp vinegar, Bay leaves, moderate number of herbs (dill, thyme, rosemary). Good beats peculiar smell of garlic, but adding it to the marinade or to the nearly finished dish, don't overdo it. Better add more fried onions. Be careful with the salt.
Do not try to get rid of the smell of too long cooking of meat. You can braise or roast it at least half a day – this will not affect the smell, but the meat will become tough and tasteless. Remember that whatever you tried to completely remove the smell you will not succeed. The strength will be only to mask its aroma of spices.