I saw Tenina do egg whites at a class a few months ago. She mentioned using the vinegar rinse of the bowl first. My notes then say 'beat at 60 degrees, allow one minute per white, speed 3, minimum of 4 egg whites'. A chef who happened to be there suggested that using reverse would also be a good idea - something to do with the chemical structure of the egg whites. I have not tried any of this, so cannot vouch for it other than I saw her do it, without the reverse bit (that comment was made after the act). I must admit I still prefer my handheld blender for doing egg whites, which I very rarely do anyway.