Flip it over and put a book on it.

Put something heavy on it for a day or two. That’s usually enough.

Mousepads are just foam and fabric (or rubber and cloth). When they’ve been rolled up for months, the material “remembers” that curl. Give it a chance to relax under weight. A stack of books, a laptop, a dumbbell — whatever’s flat and heavy. Put the mousepad on a flat surface, place the weight on top, and walk away.

If it’s really stubborn (like a thick gaming pad), try rolling it the opposite way first, then flattening. Or hit it with a little heat — a hairdryer on low, or a warm (not hot) damp towel on the back side for a few minutes, then weight. But honestly, time and pressure do the job 90% of the time.

Don’t overthink this. It’s a mousepad.