I've recently become aware of Flash cookies, or Local Shared Objects (LSO). Thes LSOs apparently are placed secretly on your machine by websites looking to track your browsing habits and do not expire. Therefore, the apparently stay on your maching forever.
I'm wondering if C-Cleaner takes care of these "super cookies" too?
More information can be read here:
https://addons.mozilla.org/en-US/firefox/addon/betterprivacy/?src=cb-dl-users