Ultrasonic CD CLeaner?

I was just searching the net for a new cd cleaner (good ole elbow grease kinda thing -- cloth and goo) and I noticed several web sites come up hosting Ultrasonic cleaning machines that you can place a CD or DVD in. Ultrasonic cleaning -- like the jewelry store uses?!?

I had never thout of that -- Is anyone else doing this? Does it work?
But most important -- Is it safe for audiophile CDs (like your $200 MFSL gold disc)? ie - no damage