Sam Stone for Bon Appetit writes:
Thankfully, Bricia Lopez and Javier Cabral, authors of Asada, a new cookbook celebrating the expansive world of Mexican grilling, have a simple solution: an onion.
Here’s their go-to method: To start, heat your grill to high (figure 450–550°). Getting the grate hot will partially do your work for you by burning off some of those clingers. Next, slice an onion in half—any kind will do, be it yellow, white, or red—but Lopez and Cabral recommend “the biggest, cheapest white onion you can find” since a larger onion will cover more surface area. Stab a large fork into the uncut side of the halved onion, then run it up and down the grate.
This technique, dubbed a piece of “Mexican ingenuity” by Lopez and Cabral, uses the natural acids in the onion to loosen and remove bits of grease and pieces of char. Onions also contain a compound called allicin, the same chemical that brings you to tears when you’re chopping. This compound has antimicrobial properties that leave your grill spick-and-span.
An absolutely fantastic suggestion for cleaning the grill.
I’m reminded of my service industry days. We used to clean panini-press grills with a similar approach. The presses weren’t non-stick and while not as hot as outdoor grills, they’d still get filthy with carbon. We’d leave set the temperature as hot as possible and set some ice cubes in between the press. Then we’d turn off the presses. The heat would melt the cubes into boiling water and steam vapor would lift caked-on cheese, bread bits, carbon and anything else that got left burnt onto them. From here, it was pretty simple. Just let the heat dissipate and using steel wool to brush any remaining bits into the grease catch.