@eschwartz -- Sorry I didn't expand on why I mentioned ePubMerge in my #1
It was the results of a tedious merge cleanup that got me wondering if there was an easy way to do some more text cleaning.
When I merged 9 or 10 stories to make an anthology for myself, the source stories had a variety of oft times contradictory styles and their own style sheets which produced a jumbled mess. Different fonts, line spacing, font size, paragraph margins, etc. Heading formatted differently, etc.
Deleting the merged style sheets and replacing and linking with my 'preferred' version at least provided an improved starting point (e.g. all <p> at least have the same basic format)
As part of the cleanup, I wanted to remove the now unused attributes in the text files to make text more lean (cleaner).
The source books had formatting like <p class="tx"> in one, <p class="txt"> in another, <p class="caliber_12">, etc. While there might be slight differences in the final formatting, they were still for me just basic body text.
Because some of the attributes were in <div>s and <span>s (and different) I couldn't use DiapDealer's wonderful editor plugin to also delete these non-value added tags also
To keep things simple for myself, since 95% of the HTML text is basic <p>, I find it's easier if I style <p> in a style sheet, and seldom add a class to such basic paragraphs.
I think that I'll use the [Remove Unused CSS Rules] the way it is intended (and recommended). I can always use PeterT's suggestion to just re-add my 'standard' style sheet should I need to for further editing