Absolutely correct. If you want it to look like new go this route. I actually went this route when I first started reloading. But for me it was a PIA and now just use corn cob. Both shoot the same. I tried ultra sonic too and didn't like it.I used to dry, vibrate tumble, and have always used treated corncob media, and it's always done a pretty good job. I used to run it for at least 3-4 hours.
Recently, I got a rotating tumbler with steel pins. I've only used it once, and was very pleased with the results.