I use an Alpha Grillers T-shaped wire grill brush. It is a stainless steel brush with a sturdy wire shaft and a long plastic handle. It also has a handy strap so you can hang it up. The stainless steel bristles will not damage porcelain grill grates or cast iron grill grates and are stronger than those on a brass grill brush, so it is safe for use with any Weber grill.

http://alphagrillers.com