They are both called tumblers in the hobby. There are dry vibrating tumblers and wet rotating tumblers.
Tumbling wet it's common to add dawn liquid and Lemishine to the stainless steel pin media. It is fast cleaning, makes bling that makes your eyes hurt looking at it, inside and out....even the primer pockets. But it requires rinsing in clean water, and a drying stage. I usually roll in old bath towels then lay them on cookie sheets in the sun for a few hours. Others get more elaborate with ovens or dryers. Winter time means an oven at 150 degrees for an hour. Warning! Stainless steeled bling is addictive!
Tumbling dry, takes a few more hours and doesn't clean as brite as wet, nor much at all inside and in primer pockets, but plenty good for most. I start a batch in the morning before work, and retrieve it at 5 when I get home. I don't care for the nut shells as it's too scratchy course for me. It gets it very clean, but don't expect new-like gloss. I prefer to use 20-40 corn cob, which consists of particles too small to get stuck in flash holes. I add a cap full of Dillon polish to give me the near-new brass look, and 1" squares of used dryer sheets to keep the media clean. I replace the sheets with every batch. Others use car polish the same way....don't use polish with Ammonia.
You are going to need a separator with both wet & dry methods to separate the brass from the media. Stainless steel media (for wet) can be bought non magnetic or magnetic.....get the magnetic.....and a good magnet to transfer media easily.
BTW, I found that corncob makes brass a little easier to size. It seems to have a slick nature to it. Tumbling wet is just the opposite. It is so squeaky clean that it is harder to size. (the best lube and careful lubing is advised).
A favorite use for dry tumbling is to remove case lube from sized brass. That takes about a 15 or 20 minute run in clean straight corn cob. A wall switch to plug timer is a good investment if you tumble.
