control + P -- Opens project... in here u click with the right button of the mouse and then clear all unused media!! This should do the trick!!!

There r 2 main ways of bringing audio into yer cubase...
1- U use the audio directly from yer folder in yer HD
2- U copy the audio 2 the project audio folder (the best way if u ask me)...

With the 2 u make sure u don't screw up yer sample library by mistake!!


Now U may have long samples that u only use a bit... so U can also do a freeze all edits...

Another way is File/ save project 2 a new folder, when u do, u have options 2 cut the samples precisely only 2 the needed bits (and only the samples used!!)... After this make sure u also save yer *.cpr (project file with yer track) 2 the same folder...

Hope this helpz,

Z