Is there a way to remove an IDE option from the external tools, external editors drop down

I want to remove visual studio 2010 from the script editor drop down in the preferences external tools area of the editor. I uninstalled vs 2010 a while back and if I double click on a script it stalls out the editor trying to open 2010. It does matter if I pick monodevelop or 2012 or 2013 in the drop down it always tries to open 2010. I even tried uninstalling unity and removing all the folders from the file system but it still has all these editors in the drop down list.

thanks in advance!