Rubber-backed mousepads can stain your desk.

Yes, especially on unfinished or lightly finished wood. The rubber interacts with the finish over time, leaving a permanent mark.

That non-slip base is usually made of natural or synthetic rubber, which contains oils and plasticizers that can leach out. Under heat and pressure from your arm resting on it for months, those chemicals migrate into the wood’s finish. You end up with a faint, sticky ghost of a mousepad that won’t wipe off.

The worst offender is dark rubber on light wood. But even on darker finishes, the discoloration can show up as a dull patch. If you’ve got a budget desk or one with a thin polyurethane coat, the risk is higher. High-end hardwood desks with thick lacquer are more resistant, but not immune.

Cheapest fix: put a piece of craft paper, a thin cloth, or a sheet of clear vinyl under the mousepad. Or just buy a mousepad without the rubber bottom—like a hard plastic or cloth one that stays put via static or weight. Your desk will thank you in ten years.