A Question about Garry's Mod gfc's?

In C:\Program Files\Steam\Steamapps\ there is a whole load of files that Garry’s Mod installed.

I only want content from DODS, and Portal. (which I own)

I don’t know a lot about these files and I don’t want to go screw up something, so what can I delete from this folder so that I only get the content I want? (I’m running low on space)

Disable them in your garry’s mod options menu first then delete them.

You can delete all of them if you really want to, it will redownload the ones you need.