CCleaner Not Cleaning FireFox Completely

After signing in to sites with FireFox and then running CCleanr, information of login is still there, If double click on username on site for exampole, my login before is still showing on small reminder box.

was FF still running?, and therefore skipped when CC ran.

or maybe FF cookies are not being cleaned.

Also is it for stored passwords that this is happening (those you've told firefox to remember)?