No oil on the Bernina paint. Elna used a very similar type of paint on their machines too. It is rather delicate and different than the vintage Singers (both the shellac and the later tan enamel paint). They can usually be cleaned with a wringed up microfiber cloth and a mild detergent. The brownish staining (if there is any), isn't from tobacco smoking, but sewing machine oil that turns brownish with age. I have gently polished my Bernina 730 and 900 with resin type car polish (liquid). It will lift up any stubborn grime and dirt, but be carefull with logos and letters in the paint, they can sort of disolve if you do it to hard. Don't rubb too hard on these at all. I think the car polish leaves behind a protective film, even if shouldn't be done too often, I think it helps. After a clean up and polishing of a dirty machine, you can use the clear non-gritty version of this polish. You might need the one that dries to a whitish film the first time to lift up old dirt and grime completely.
Last edited by Mickey2; 12-01-2020 at 04:18 PM.