Light Linking in Maya may appear at times to be black magic, this tool aims to
demystify it and make fixing problems effortless for any user.
Unfortunately, some light linking tools/scripts actually create more problems.
This tool is designed to safely clean scenes anytime, and additionally provide
tools for efficiently light linking. For more info, read the full help docs.
Download MayaLightLinkTool here (contains 1 directory with readme, and 2 python scripts)
Example of before and after cleaning: