falzedar said

I logged into firefox sync to work on homework at a computer at my work. Now even though I am signed out of sync, my bookmarks are still accessible. How do I sign completely out so none of my information can be reached?

After signing out of Sync, close the browser completely and reopen it.

you connect to Sync then data on the Sync server is merged with existing data on the computer. That is why you should only connect to Sync with a trusted computer that is your own. You will probably have to remove synced data manually yourself.