Gladly!
http://blogs.scientificamerican.com/observations/2011/07/02/whats-in-your-wiener-hot-dog-ingredients-explained/
Basically the refuse you would normally feed a dog. The next time you let your dear friend gnaw on a bone, look at the scraps of meat, tendons, cartilage, Etc. That is what a "Mechanical separator" does. It blasts the carcass of the animal after all the "Choice Cuts" have been removed. So basically they pressure wash the carcass and recover the water which is carrying bits of whatever. OH! Let's not forget "Stock". Not your mothers recipe. They boil the skeleton, marrow, joints, knuckles, whatever, and use the juice for flavoring, YUMM. And the average hot digity contains 20% of your DAILY sodium intake.