Your rubber mousepad might wreck your varnished desk.

Yes, it can, and the surface finish definitely matters.

The issue is plasticizers—chemicals that keep rubber soft. Over time, especially with heat from your wrist and pressure, they can leach out and react with varnished wood, leaving a sticky or discolored mark. Raw wood is more forgiving because it’s porous and doesn’t have a sealed layer for the plasticizers to bond to. That said, cheap rubber can still leave an oily residue on bare wood.

I’ve seen it happen on a nice IKEA desk after a year. The varnish turned tacky, and nothing would clean it off completely. On raw wood, you might just see a faint ring you can sand out.

A felt desk pad underneath your mousepad solves everything for twenty bucks. Don’t risk your desk over a five-dollar mousepad.