What to do with expired BRP

Hi All

I have finally got my new BRP. And I still possess my old expired BRP.
What should be done with that?
I read in this forum somewhere that it shoud be returned to border agency.
But I did not get any instruction from either government office or my company?

can someone please help me here what address to send it to and the official/formal statement by home office?

Thank you

You need to cut the old BRP in quarters and Send to

BRP Returns
P O BOX 195
Bristol
BS20 1BT

Keep the proof of postage for future reference