From my experience, I personally try to stay away from WD40 since it is a penetrant and will eat away at certain polymers and plastics. Considering that major components of the grip and parts of the slide are plastic (Not to mention parts of the Magazine in the .40 HP), I'm very wary of using it on my HP's or any firearm. Now, if I'm completely stripping a millsurp arm like an M44 or the like, then WD40 might just be what the doctor ordered for cosmoline removal.
Any other input?
Any other input?