Before you mount a hide that smells bad, add some OdorXit to the water you soak the hide in and let it work (1 or 2 ounces per gallon of water). When you are ready to mount the hide, the odor will be gone, and in a few hours, the OdorXit smell will be gone too.
This process works for fish too. After removing all the unwanted material, you can spray the skin inside and out with OdorXit diluted 1:30 and mount the fish. This action will cut many days off the waiting time to finish the project.