How to clean up speaker

@heriyadi there is really not much you can clean on the speaker itself. Check this video at 5:30min you see where the speaker is and what it looks like.

Usually all you can clean is the speaker mesh from the front panel with some isopropyl alcohol and cotton tip applicator. The only other way would be to remove the speaker as seen in the video. Then clean the panel from the inside. If you want to go that way, replace the speaker completely, just in case your speaker issues are related to the speaker itself.