RH 11 v11.0.2.240: Cleaning up an External Style Sheet (CSS)

Hello,

I am in the process of trying to clean up a CSS for an "old" RoboHelp project.  I believe the CSS contains many unused styles that were probably "trial & error" styles, but were never deleted when they failed to produce the correct format.  I know it doesn't do any harm to leave them in the CSS, but I really don't want them around! 

I did not see a report in RoboHelp that would provide this information, but before doing a search for each individual style using a program like Agent Ransack, I wanted to see if anyone in the Community had any clever ideas as to how to accomplish this task.

Thanks for  your input/suggestions!