My 2cents and "secret method" lol for RS400 aluminum handles. Bon Ami cleanser and a microfiber cloth with water. It cleans and polishes all in one to an absolutely brilliant luster and follow with 3 coats of my own carnauba & beeswax wax I use just on razors. You can use the protectant of your choice to prevent deoxidation provided the full on brilliant shine is the look you desire. Using this method you can restore these brushes in record time but that's not why I like it. The results for such little effort is amazing.