Auto grease is full of heavy metals; moly and several others. If it's not fit to use on a human, it's not fit to use on a living animal. Use petroleum jelly, available at any drug store or Walmart. While I wouldn't eat it, it is safe to use topically on animals.
Not that I agree or Disagree, but just to balance the argument, most human medicines are full of toxins and poisons too.
Some, not most. Yes, I am a health care professional.
Petroleum Jelly is all "that's in there".