Deleting certain filetypes from folders

I am running tvrename to move over my tv shows/movies to their specific folders but there doesn't seem to be an option to only scan for certain media types so when I run a scan it comes back with all the nfo files for that episode or movie.

I would like for tvrename to only scan for .mkv or other media I specify and exclude files like .nfo but it doesn't seem possible in tvrename.

I am wondering what you use for cleaning out specific media types in your folders?

Thanks!