MTS Files in Final Cut Pro X deletion and space question...

[Scott Goldberg]

So, I did a lot of uploads for certain clips a while ago doing test shoots and they are on my side bar for where my clips are in FCP X. If I delete them from the side bin, are they (the file and space they take up) out of the FCP program for good? I ask because I want them to be. I'm not sure if they're saved and taking up space in some area where I cannot see that it's taking up space in...can anyone confirm this?