I use a scotchbrite type pad to get rid of any existing rust on my cast table tops and then re apply Johnson's. When my various machine cast table tops were new, they tended to want to rust quicker/sooner after a waxing, but, as time went on, the wax protection seemed to last longer and longer between applications. I now wax mostly for the "slickum" factor rather than to attack any rust. I don't clean the old coat of wax off, just smear a new thin coat on and immediately buff it out with a soft rag to restore to slick feel. I wonder if the table top "pores"? are filled with wax and now better protected?