Hello and welcome,
You can, but that would only free up about 425 MB or so. Things like movies/videos and applications take up far much more room.
-How much free space do you have?
-Do you have any purchased iTunes movies that you could delete, since you can stream them or re-download them later?
-Have you checked your Downloads folder, and removed any large installers or other files you may not need any longer?
-Do you have a current Time Machine or other backup as a safety net?
C