How do carb restorers clean the outside of the carb?

It's not so much the cleaning solution as it is the cleaner machine itself. I heard theey are blasted with walnut shells like the ammo re-loaders use to clean and polish bullet casings.
http://cgi.ebay.com/New-Commercial-...C-CLEANER-/310242314026?pt=LH_DefaultDomain_0