I agree with Brett, Sr.'s advice. If you can stick these things out away from houses, and working buildings, so you don't offend people with the odor, let the birds and bugs do the work for you.
Otherwise, you have to boil them, and its a very stinky process, no matter what you do. You can put bleach in the water to help kill some of the smells, but its still a stinky job to loosen those cores enough to pull them out. One man here told of useing large lag bolts screwed into the cores, to pull them out of the horns. Sounded like a good idea to me.
I boiled mine over a BBQ grill on a good windy day, so that the stench was swept off as fast as possible from the neighborhood. However, If you were outside, you could smell it!