So many resturants use wire brushes.
The last burrito I had was a few months ago. It had piece of wire in it. I kept the wire for a few days, and thought about it. The wire was not from a brush. I think it was old copper telephone wire. It that might have fell onto the grill from the ceiling, or wall?
Anyways, I haven't had a burrito since that instance. And tonight, I just got the visual of them cleaning the grill with a big, old wire brush--with gusto. Now I think about it, they had all types of black brushes near the grill.
Those grills are just large pieces of steel, without holes, or spaces. If loose wire isn't caught by the cook it just gets mixed in with the of steak, chicken, whatever.
(They make small metal detectors. My watch parts supplier is always advertising them. They claim they will find watch parts on the ground. I wonder if they could detect those small bristles?)