Lemon oil will not harm paint. One of the most common uses for it is to maintain the finish on stainless steel appliances. It is not acidic. It has been used for years by used car dealers as a way to enhance the looks of a car, it really gives them a deep wet gloss look, but only for a short time as it wears off. I used it a few times on my other car after seeing it done. It did no harm at all. Just doesnt last that long. Its like cheating on a good wax job.