I'd think that I would find out if the fridge works before investing any time in cleaning/referbishing. As far as painting
, most paints woud give up in short order in the conditions inside a ref. It's not just cold, it can get very wet as well. Plus there's the thrill of having your food taste like fresh paint.
BTW: Most of those inner panels are a plastic of some sort, acetone will melt most plastics.
I would opt for rubber gloves and a strong bleach solution for cleaning and disinfecting.