Why do files deleted from a shared drive not show up in the recycle bin?

My recycle bin shows deleted items when they are deleted from my desktop, but they are not showing deleted items that have been deleted from our public drive (shared drive that everyone with appropriate log in can access). Where are they going and how can I get them to delete?
One more thing...when I open the recycle bin to try to erase all, that isn't an option, so I don't think it's an issue of files being hidden. I can see files deleted from local pc, just not drive from the server.