They're called Ultrasonic cleaners and are mostly used for cleaning up jewelry. There are plenty of examples of them on ebay for home use, such as this one. I paid £22 (around $30) for mine and put it through it's paces.

It works by using ultrasonic resonance in a body of water to create cavitation - tiny explosions that separate the items from any debris or foreign substances.

It's paticularly effective at intricate pieces (such threaded components, drip tips, anything hard to reach by hand - gets in there and cleans out all the crap).

Would seriously advise these if you have a lot of tanks, different rebuildables, and want to make them look and feel like new again.

The only thing it won't do is polish up your metals, but it would be a great pre-wash before you do any touch ups anyway.

And of course, not using a toothbrush will mean les chance of causing damage and should make your equipment last longer.

I also use this to clean out syringes for DIY, which works a treat.