5/10/2021: Summer is approaching, and for many people that means that it is will be peak time to fire up the grill. There have been many stories about the danger of cleaning your grill with a wire brush, as sharp particles and splinters can break off of stainless steel- and brass-wire brushes. If that happens, those particles can become imbedded in future cooking, and result in significant risks if ingested.
However, wire brushes are efficient at cleaning a grill, and can be safely used, but they do require some common sense. There are two ways to approach this, and either can be right if you do it properly.
When the cooking is complete, wait for the grill surface to cool down to where it is still warm but not cool. Then, using a good quality wire brush, sweep off any food particles. Doing this when the grill is still warm makes it easier to scrap away food particles that, once cooled, are baked on, potentially containing wire slivers. Conversely, if you don’t want to bother cleaning at that point, you can wait till next use. At that point, though, you should pre-heat the grill at a high temperature for an extended period (at least 20 minutes). Then, place a wire brush into a bucket of warm, soapy water, and scrub off the surface of the grates.
Whether you reach for a wire brush before or after cooking, give it a close look. See if it has any broken bristles, or if it is worn or warped. If anything looks iffy, discard it.
As an alternative to wire brushes, Consumer Reports recommends cleaning with a coil brush, pumice stone or abrasive pads. Good Housekeeping suggests crumpled aluminum foil and a strong degreaser. And, for those who like a natural approach, consider the following: pre-heat the grill as described above, then slice an onion in half. Pierce the onion with a fork, and run the cut-side down along the grill grates. The onion's juices will release and produce steam to remove the bits and charred-on debris.