Real space saver!

An excellent app, that works with both legacy FCPX and FCPX 10.1. (You do need to drag the entire disk on which legacy files are located to the app in order to have them "wiped").
Further, the folders must be named "Final Cut Events/Projects" -- not with the "- Hidden" title, or the app doesnt work at all.
The developer is very responsive to comments/bug reports.

rb42 about X-Wiper