Download of UnusedStringsCleaner 1.1.2 for Mac was on the developer's website when we last checked. We cannot confirm if there is a free download of this app available. This free software for Mac OS X is a product of Brain Tools. The application lies within Developer Tools, more precisely Webmaster Tools. Please check the Mac app with an antivirus before launch as it is downloaded from the developer's website, and we cannot ensure that it is safe.
From the developer:
UnusedStringsCleaner finds unused or duplicate localized strings in your Xcode project. The application can compare Main.strings and Localizable.strings files to find duplicate keys. In addition, it has the ability to convert Main.strings into Localizable.strings.
You may want to check out more software for Mac, such as Url Extractor X, Boks or WebPics, which might be similar to UnusedStringsCleaner.