I use granite landscape chips in some water to knock deposits off kegs. Just shake.
Tim

Some pretty damn clever ideas, there, particularly those stainless
steel balls.

As an avid homebrewer, "stainless" could be my middle name. I did want
to warn folks on this thread that I would never just rinse a keg and
then use it for ANYTHING. I always sanitize and try to sterilize. This
means, like one of the other posters on the thread, using a sodium
percarbonate solution. This usually works great. I'd like to add that
99% of things come out by letting it sit overnight. People don't let
time do the work for them. They are too impatient.

After I do that I rinse, rinse, and then rinse again. Finally, I do my
best to sterilize, and that means using an iodophor solution. A few
fellow winemakers I know skip this step, but they also have had
problems. Knock on wood, I try my best to sterilize all my equipment
before use, and so far, so good.

Also, I wonder if the look that they are describing might not be just
the low gloss finish used on typical stainless. It isn't polished up
to a chrome like shine inside of a keg, like you'd see in stainless
cookware. It is more like a matte finish, or like a brushed aluminum
look.

Hope some of that is helpful.

Regards,

Deadend