You can remove a rule from a site by clicking on the appropriate cell in the dashboard. Clicking on a cell cycles through the available states for that rule for that site. The icons that indicate that a rule is marked for removal from a site are:

The latest version of this rule has been queued for removal from this site.

The modified version of this rule has been queued for removal from this site.

When either of these icons is displayed in a cell, the rule is queued for removal from the site and will be removed from the site the next time the site is published.

You can also remove a rule from a site by going to the Associated Rules screen for the site, clicking on the action cog for the rule and selecting Remove Rule from Site from the command menu. Any changes made using this method will also be reflected on the dashboard.