When I was a kid I bought a baseball glove. Dad mentioned I should oil it so of course I used 10W-30. I still use that glove to play catch with my kid. The leather on the inside has pretty much rotted away but the outside, the part I rubbed the 10W-30 into, is worn on the edges but otherwise in great shape considering it's age.

You should try 10W-30 MT.  :thumbup ;) Happy B-day!