If you are in the UK you can get Dry CrOx from
Green Chrome Oxide Powder Strop Dressing for Razors 5gm on eBay, also, Barber Shop Shaving, Vanity Perfume Grooming, Collectables (end time 03-Feb-09 00:02:14 GMT)
£4.99 5g Free post

I mix it with a little oil & use it to polish razors before the metal polish.
Works great.