It depends on how you broke up and the agreement between you. If you have already reached an agreement at the time of the breakup, for example, there is a clear agreement on the ownership of the clothing, then it is more appropriate to deal with it according to the agreement.
If you don't come to such an agreement, then you can consider the following options:
1.Send it back: If you feel it's fair and appropriate to send it back, you can pack your clothes and send them back to your ex-boyfriend by courier or post office. It's a good idea to take photos and make sure your clothes are clean and tidy before sending them to avoid any disputes.
2.Donate: If you don't want to keep these items anymore, you can choose to donate them to charity or someone in need. This will not only reduce your burden but also help those in need.
3.Discard: If you don't want to dispose of these items anymore, you can choose to discard them. But before throwing it away, you need to make sure that the laundry is clean and tidy to avoid polluting the environment.
Whichever way you choose, you need to make sure that your actions are reasonable and legal and that you don't cause any harm to others.