safely deleting files in fcpx

so now that i have the final cut library manager, what files can be safely deleted?
it list:
optimized, proxy, flow and rendered files. if i delete all of them, can they all be regenerated upon opening the library? I see how the rendered files regenerate when i open, but not sure how the other files work.
thanks

They can all be regenerated. For proxies and optimized, select the clips, right-click and choose Transcode Media. Optical flow analysis files are generated whenever you go to a clip in a project that has it applied.

IF you use Optimize during the Import process, I don't think you want to delete those, if I'm not mistaken, they're all you'll have.

You should still have the original media unless you manually deleted that.