To remove a paragraph style, do this:
where myParagraphStyle is a reference to a paragraph style in the document.
For instance, you could get a reference to a paragraph style like this:
This implies that you have a document open and that it contains a
paragraph style called "Chapter Title" outside of any paragraph style
whether a given paragraph style is unwanted by the user.
Possibly, if there were a freak electricity spike in the mains just as
you were running the script, and if God were smiling upon you, then
perhaps the paragraph style that you consider unwanted would be deleted,
but I would not rely on that for production purposes.
Do you mean unwanted or unused? As in Select All Unused from the paragraph styles menu?