Most of the rasp-style graters we tested come with a cover for the grating surface—and for good reason. The graters’ teeth actually poke outward slightly—that’s how they bite into the food. These 3-D teeth can flatten out over time as the graters get thrown into drawers or slid into utensil holders. If the teeth on your Microplane Zester/Grater feel dull, it’s probably not that the teeth’s blades have dulled but that the teeth have flattened, so they don’t have the same bite.

To fix this problem, you can go hole by hole and poke them back out if you’re feeling especially coordinated and have lots of free time, but we prefer the preventive route.

1. Use the cover that comes with your grater to protect the grating surface.

2. When using the grater, try not to press down on the blade when sliding the food back up for your next swipe.

3. Dishwashers are great for cleaning food from the opening in the graters’ tiny teeth, but items inside the dishwasher do bang around during the cycle, which can damage the teeth. If you really want to preserve the effectiveness of your grater’s teeth, you could rely solely on washing by hand, but we still run ours through the dishwasher in the test kitchen because it’s easier.