I was polishing some cases today and after 4 hours I expected bright shiny brass but it wasn't. Some were pretty good, others not so much.

So, I wondered if there was anything I could add to the media. I came across a forum where somebody suggested that some cat litter was made from crushed walnut shells and he used it all the time. A little more research revealed that "Natures Calling" cat litter is indeed made from crushed walnut shells, and can be ordered from Pets at Home for £12.00 (4kg bag) which is about 1/4 the price of Lyman.

Gotta be worth a punt.