The code I sampled here can be used in a regular text link, the submit button or even by loading the page with url parameters. If you have access to a JavaScript developer, it should be clear how to implement it. On my pages, I leverage it whenver the page is loaded with the url parameter userId=guest, so I simply use a relative text link on the page that links to the same page itself, including the url parameter.
i.e. If the form pre-populated below is not you,
< a id="mktoGuest" href="?userId=guest">click here</a >
But you could also invoke it by calling the function from a regular text link.
The reset button does not necessarily clear the cookie values, just the field values but the person might still be recognized, so I ensure to remove all traces by doing both things at the same time.
I hope that helps clarify it.
Rafael