OK thank you both for the explanations. Now how do you know grease is bad other than being dried out? Does it smell bad/rancid like cooking oil does?
In my opinion I would think the older greases would be a lot better than what we have today because it didn't contain additives. It was just plain old grease and it did the job for many, many years. I think it was when we started adding stuff to it to make it supposedly more effective and go further it started not lasting. Many times the old would be scooped back up and placed back where it was supposed to be. Back in the day most things followed the K.I.S.S. rule. Now we have things so complicated to cover up the fact that it doesn't last and isn't as good as the original stuff. When we clean these old machines we find that the old grease isn't so much bad as it is dried out. If it could be reconstituted I believe it would still perform like it did when it was new.