What the lemons do is actually pretty simple. When two cut lemon halves are left inside a turned-off oven overnight, they can help freshen the space and soften some of the stale, heavy smell that tends to build up inside over time. Their natural citrus oils release a clean, sharp scent, and that can make a noticeable difference in an enclosed space that’s been trapping cooking odors for weeks or months.
That’s the main reason people do it. It’s not about pretending lemons somehow deep-clean an oven all by themselves. It’s about making the inside feel less stale, less greasy, and less unpleasant the next time you open it — especially if the smell has started bothering you more than the mess itself. And in some cases, the leftover moisture and citrus can also make the inside feel a little easier to wipe down the next day, especially if there’s light residue or surface grime that hasn’t fully baked itself into the metal. That’s really the appeal of the trick.
It’s simple. It’s cheap. And it makes a gross-feeling chore feel a little less gross. Sometimes that’s all people need.