Buy all means, do not use the grit of sandpaper specified in that article. I play on tables with those balls and they are terrible. 60 grit sandpaper is way to fine and will not bring the balls back to factory specs. Steve Marshall is the guy in the picture and is a great guy, so anything I write here is not in any way a slam on him or the way he keeps his tables. For some reason the balls he refurbs roll way to fast and when you shoot a pull they stick to the surface like bubble gum.
The factory used a commercial dryer lined with 20 and 24 grit norton sandpaper. You will find it in the floor refinishing area at Home Depot or Lowes. I bought a used gas dryer for $25 and spent another $35 on sandpaper and glue. I gave mine to Spirit Mollice a year or so ago. You could probable pay him to tumble you balls for you, but you will have to wash them first. Honestly, you can not tell the difference between brand new and refurb balls if you will use the courser grit I am reccomending here.
Good luck
Ed