My old man use to have a splitty and loves getting in my Kombi for a drive. Hes 89 so I put in a handle on the door frame so he call pull himself up and in. Used the two screws that came with the handle and two gal self tapers I had. I pre-drilled the holes. Should I remove the handle and paint the holes to prevent rust, or pour oil in them, or, as its internal, is rust unlikely to be an issue?