Deregister at commune Brussels 1000

Hi All,

Am leaving Belgium in 2 weeks and need to deregister at 1000 commune. Anyone know the procedure to follow? I searched this site and tried calling them but they didn't answer, and it's a horrible commune to visit so would prefer some advice upfront if possible, rather than go in the morning and wait around half a day. I understand I need to hand my residence card back.

Hopefully deregistering will be easier than registering...