Once it clears generally everything is gone and if they clear the history or cache options that basically wipes all traces. If your concern of their usage make their own account to use and then you can have Admin control how they use the accounts. But usually if they can clear cache or history there's nothing you can really do at this point.

Dropa, Then how does the law departments see what a person says if they thought he/she committed some kind of crime?

That is with the ISP they have the history of the tracking. I think this is going beyond Firefox forum help. And you need to seek advise not from Firefox for what your asking.

this is completely out of my wheel house. I have no idea what anyone wants from me. I feel stupid which is why i have asked for a walkthrough of info just so i have it right. This is too complicated for me to process all of the information from the past plus do real time stuff here. Please can we just leave. I so badly want to see and talk to you just for small talk and comfort. I am not looking for spefics of info other than a adult safe and potentially steamy life of sex. Sorry Simple Girl just needs simple fix to solve this issue. I need real life face to face interaction for my brain to process thinhgs correctly. Please I am begging you.