I think you are suppose to use sewing machine oil only so you don't remove any of the scroll work while cleaning. That's what I used on my 15-91 and it did clean it up nicely. Better wait for the experts to chime in before you do anything though. They can steer you to the right place to look on this board or you can put your search words in the search box at the top right of this page and you will find lots of info.