The BS filter has been an option for a LONG time, and has been publicized often. All you need to do is set your Mudcat bookmarks to the following URLs:

http://www.mudcat.org/threadsnot.cfm?Title=BS:

http://ragtime.mudcat.org/threadsnot.cfm?Title=BS:

http://loki.mudcat.org/threadsnot.cfm?Title=BS:

Once you are in the forum page, after opening a thread you need to use that URL and the browser's GO button to re-filter the thread list. Use it also instead of the Mudcat's REFRESH button to reset the page whenever needed.

~Susan