This works on a Mac - not sure about windows, dont see why not - itās a regular expression.
Open a playlist in a text editor, use the find and replace function, set the search as regex, search for:
(.*?) - (but put a forward slash before the first round bracket and after the question market (this forums text processing is removing them within this post))
and leave the replace box blank. Any text between round brackets is removed, along with the round brackets. i.e (U), (USA), (E) etc
Try Notepad++, thats a powerful text editor for windows. I use ancient but trusty Textedit on Mac.
Be careful non of your actual roms you are trying to load via the playlist contain brackets in the file name.