How do I remove security certificate exceptions from Google Chrome?

I've finally found the answer.

On the address bar, click on the padlock to show the certificate details. In the Connection tab there is a button "Stop using this certificate". Click it to remove the exception.

Chrome looks a little different these days, so here's an updated picture of where to re-enable the warnings.

You still begin by clicking the "Not secure" indicator to the left of the URL. Then, in the panel that pops up, you click the "Re-enable warnings" link.

01/2017 - After many Chrome updates, now you just click to the left of the URL, where the padlock is, or if something else (mine is a local server, displaying a "red triangle Not secure"), click that to display the information about the connection, then click "Re-enable warnings"