how do you remove cookies from a URL?

Cookies are entirely dependent on the browser cache of the end-user / recipient of the email, there isn't really anything you can do if a lead has already been cookied.

Regarding URL tracking, if you normally build landing page or email URLs with "utm" tracking parameters, just delete those from your links and resave.  Doing this still won't affect any information carried around by a lead via cookie, however.

Out of curiosity, what is the use case here - why do you want to remove all tracking info?

@Nate A You can't delete the user's cookies if they don't visit your website again, but if they do follow a link, you can certainly clear their Munchkin cookies before loading Munchkin.js, therefore making a new anonymous lead for subsequent page views.

I think the easiest answer here is what Justin provided, using the class mktNoTrack (which is case sensitive). A visit to your site will still cookie someone unless you have disabled that feature, but you will not have insight into who clicked on the link in an email and it will not be a tracked link. 

mktNoTrack will have no effect on cookies.  The only solution for the OP's requirement "remove the cookies" is to not load Munchkin.js at all.