Thanks Trumpy.
I looked over all the info I could find on leather protectors from North, Salisbury and couple of other brands, but they donít seem to mention anything about using any leather treatments or waterproofing on them.
They all pretty much say the same thing... that their HV gloves made from natural rubber should not be exposed to ozone, UV, hand lotions or creams containing Lanolin or petroleum, yadda, yadda, but no mention of animal based pure neatsfoot oil.
I see that Salisbury has an improved HV glove material called Salcor that is supposed be resistant to breakdown from these contaminants, so maybe those might be a better option in this situation.
I do find this situation a little odd though, because pure neatsfoot oil is exactly what the manufacturers recommended for use on our climbing belts, climber pads and straps as well as pretty much any other lineman's gear made of leather.