Got crayon marks on your wall? How about scuffed areas along your baseboards? If so, you’ve probably reached for a Mr. Clean Magic Eraser before. These handy little sponges seem to magically remove marks, but have you ever wondered how that ‘magic’ actually works?

As it turns out, Magic Erasers aren’t like other sponges at all. In fact, they’re made of an entirely different material called melamine. When it’s in a solid state, this compound makes a powerful scrubber that won’t damage other materials.

Melamine is also porous—if you’ve ever used a Magic Eraser, you know it feels hard and slightly rough. Essentially, it acts as sandpaper on marks, scuffs, and stains.

The porous structure of melamine is created by tiny air pockets, and they are what help scrub off stains. However, they do need to be activated with water. When that happens, these tiny pockets harden, and the connections between them pull and drag the soiled item off the surface.

Over time, Magic Erasers start to break down, due to their porous nature, but they’re extremely affordable. Plus, because they don’t require any additional soap or detergents, the sponge is all you need (and some gloves because that’s a little too much exfoliation).

While you should always perform a patch test before going to town, this product is generally safe for most surfaces.

If you’ve been looking for a way to remove your kid’s Sharpie drawings from your wall, just grab yourself a pack of Magic Erasers.