My black set was a disgusting mess that had sat for more than 20 years. I soaked them, buckles and all, in a bucket of warm water and OxyClean (@ high strength). Used the soft scrub brush and repeated once. Rinsed several times. They came out like literally like new and the buckles were beautiful too. The best part was that my manufacturer tags all came out a nice shade of white too, with no damage to the printing!