I am in the Johnson's Original Paste Wax camp for the protection and maintenance of the ways.
If you buy the Johnson's Paste Wax in the floor wax section (and it does not say "Original"), then it has the OSHA-mandated non-slip additives. You want the Original version sold in the furniture wax section.
WD-40 is not a great choice for cleaning (or lubricating) despite many people using it for both. It is a Water-Displacement (the 40th formula tested (hence, the WD-40 name)) material developed to inhibit rust on clean iron/steel. Once it dries, some of its ingredients can actually encourage galling.
If you have light surface rust, then Autosol and a paper towel is a good cleaner.
If you have tree sap or a finish stuck to the steel, then you want a cleanser specifically for the crud or just some wet paper towels. Let dry thoroughly and then wax.
Be sure that you move the banjo, tailstock, and headstock (if applicable) back and forth during cleaning and drying to be sure that none of the liquids wicked in underneath without getting dried off.
If you are wet-sanding plastic on the lathe, be sure that the ways are dried off thoroughly at the end of the day. I know a couple that had some "discussions" about that issue. She did not always dry off the ways after turning plastic pens and he would find the surface rust when he went to turn the next day.