Apologies for my late reply. The reported bug in cutils2.py has already been fixed along with several other plugin problems but I'm unable to release the new version(v0.5.0) yet for good reasons -- I'm in the middle of a major plugin upgrade. The new version of this plugin will
not be able to process imported HTML files in Sigil as before -- but it will be able to clean up both EPUB2 and EPUB3 files. I have also fixed many other small problems in that plugin and have also extended it's automatic capabilities as well as added several more user options which I hope will be useful. I've also had to do a massive cleanup of all the plugin code -- in order to remove all the unnecessary code for html file cleanup.
Because I've removed the plugin's ability to process html files I've also had to write another new plugin -- tentatively called HTMLCleaner -- that will just be dedicated to cleaning up html files that are derived from Word or LibreOffice only. I have also added many new and extra features to this plugin as well, including a new "nuke" feature that acts to preserve all text but removes all classes and inline styling, ultimately removing or reverting all html tags to basic <p> tags.
Both the new version of the CustomCleanerPlus plugin and the new html cleaner plugin will be released at the same time, otherwise people who have been regularly using the original CustomCleanerPlus plugin for html cleanup might complain. So my intention is to release these two plugins at the same time which seems the fairest way of doing it. I'm currently busy testing both plugins at the moment, so please bear with me.