When I close Firefox I want it to automatically clear the contents of anything that I have previously used in copy/paste editing
Simple really! I dont want any information I have copied using cut / paste / copy functions to be available once Firefox has closed. Dont want any other users of PC to come along say using Word ....right click ....paste ...my information / data is there
How can I stop this please
Type about:preferences#privacy<enter> in the address bar. The button next to History, select Use Custom Settings.
At the bottom of the page, turn on Clear History When Firefox Closes. At the far right, press the Settings button. Turn on Cache and Form And Search History.
You mean that you want to clear the clipboard when you close Firefox?
You could consider to use Private Browsing mode if you do not want to leave trails.