Try RomLister! You should definitely be able to filter out CHDs with that. Japanese games are a bit tougher - you may need to go through by hand and just delete anything that's obviously Japanese. Anything that's not obvious may be something you want anyway.
You can also easily get rid of not working games as well which will help free up space. Also easy to filter out are mahjong, quiz, mature, and casino games (unless you like playing those of course, but most people trying to cut down their romset dump them) as well as games that require controls you don't have. No point having lightgun games for example, if you don't have a lightgun.
Hope I helped!