Not a Dr Who gadget

There's a thread on the Reaper forum just now about ultrasonic knives and dental scaling gizmos for cleaning mold lines -
linkI was wondering if anyone here used such a thing. I've looked at the Phrozen one, and watched a couple of YouTube videos -
Amazon UK link, but it's well past the "impluse buy" price point, so I thought I'd ask the collective first.
There are also various dental scalers and cleaners, so if anyone has any experience with them, I'm also interested. Having just spent an afternoon carving flash off Reaper Bones USA (Siocast) and normal Bones figures, anything to speed that up would be welcome.
