You don't say what browser you are using ?
But that should be easy to resolve in your Browser Settings function, look for History, or Options, etc. It is likely to be under Privacy, most will allow you to clear cookies, etc. on closing your browser or just clearing existing history. See attached example from Firefox.
If you clear history/cookies, etc. on closing your browser you may need to enter log-ons again unless you have saved them elsewhere.
A search on your topic subject Clearing Cookies should also help you, more so if you also include your browser in that search.