ResXManager is another great free tool that integrates with Visual Studio.
From the site:
You can quickly navigate through all resource files and view the content in a well-arranged data grid. It makes it easy to find untranslated strings or clean up orphaned entries. All strings can be quickly edited in place, …
The tool is still updated and is available as VS2012-2017 extension and standalone executable to support VS2010 and older.
