When I log off,I find that when I hit the go back key,I'm right back into my email which is a security concern

I do not seem to have the same problem with my other email addresses and clearing privacy info in Mozilla tools does not help consistently. Besides, I have to remember to do this each time which is a hassle. Please advise.
When I log off,I find that when I hit the go back key,I'm right back into my email which is a security concern
The reason it does that is because of the browser history. Set the number of days it stores the history to 0. Then it won't save the history.
Reply:Anytime i log into a site, when i log out i close the browser. Then re-open a new window to surf.
Reply:Close your browser when you're finsished with your email.