disk cleanup can do more than temp files. When you run the wizard it will prompt you with things. You can empty the Recycle Bin manually if that's what you are talking about, right right-click on it and select Empty.
Another trick to free up some space is to change the I.E. temp files space, set it to 100MB or something, I have seen that set to 1gig on many systems which is a bit much. Then empty the I.E. temp files. If you are not too worried about needing to uninstall MS Service Packs, you can to into the Windows directory and delete any of the files that start with $, are in Blue and say NTUninstall and such.