If I were you I'd leave it until it stops working, they all rattle especially if you have semi synth oil. My alp rattles like a bag of spanners but goes OK albeit slowly.
If when warm you are in gear with the clutch in and at stand still, you rev the bike and it seems to pull and try to move forward then the basket has grooves on it which need filing off. If you rev when in gear and you go no where then you need new plates, non of which are more than an hour or so to fix so until either one of these happens I'd let it rattle. I personally also make sure cables are all OK as Ive at one point thought i had a brokenn clutch which turned out to be a cable which needed replacing
hope this helps and I'm sure more mechanically minded people could add to this