How to block access to a shared or public metric

You can unshare your metric at any time. Move the cursor over the metric, click on a sharing icon  and a sharing options will be displayed with a list of your shares. Each recipient on the list has a ON/OFF switch. Unshare it by switching OFF. You can turn it back ON at any time.
You can also remove this person from your sharing list by clicking the delete icon 

Proceed the same way to remove your metric from the public catalogue or deactivate a sharing link.