Grill Cleaning Hacks — Tested! We’ve test the popular grill cleaning hack of cleaning grill grates with an onion. To clean dirty grill grates with an onion follow these steps: Cut an onion in half, stick it with a grill fork and scrub grill grates while they’re hot. Have you tried this grill cleaning hack? Visit the Sears Home Services Knowledge Center to watch the video and find out if this hack, and more grill cleaning hacks, actually work!