In SharePoint 2013 there is a new feature. Every list that is added to the Current Navigation appears under a heading Recent.
Simply add the following css:
#sideNavBox li > span
And the recent heading disappears. This uses the idea that the Recent Heading doesn’t have a url set and therefore it contains the spans directly within the li element.
There is only one downside that I have seen so far and that other headings without a link will also disappear.
One important thing now to make your lists appear in the left hand navigation the Static display levels will need to be corrected I the master page used by your site. If you use a seatle.master based master page search for StaticDisplayLevels=”3″ and replace it withStaticDisplayLevels=”4″
Update: Recently I found an easier way of hiding the Recent option.
Create a SharePoint group “Nobody”
Go to Site Settings and Navigation
find the Recent item and click on Edit.
Now set the audience targeting to the Nobody group.