I have never used after run oil and never intend to. I live about 5 miles from Tampa Bay a very humid area. Never have any rust and many engines lie idle for years at times. Also never run the engine dry, just drain fuel from tank take it home. just lazy I guess but don't have engine problems. Why I don't know, but guess lazy, lucky? Been doing it that way for at least 50 years. Have had I guess almost every engine made from T D's to Saito 4 strokes and Sachs gassers. Suit yourself.