Why has my mouse gone sticky?

The soft-touch coating is breaking down. It is a thin polyurethane layer sprayed over the ABS shell, and it hydrolyses over a few years — absorbing moisture from the air and reverting to a tacky film. The plastic underneath is unaffected and the coating can be removed completely.

Why it happens

Soft-touch coatings are used because bare ABS feels hard and slippery. The trade-off is that polyurethane and atmospheric moisture react slowly and irreversibly. Warmth, humidity and skin oils all accelerate it, which is why a mouse handled daily goes first while an identical one in a drawer does not.

Nothing about this is a defect in your particular unit. It affects any device with the coating — mice, remote controls, camera bodies, older laptops — and it is why some manufacturers have moved back to textured bare plastic.

What to do about it

1. 1Isopropyl alcohol on a cloth removes it. Work in small sections; it will feel worse before it comes clean as the coating lifts.
2. 2Expect to repeat the pass two or three times. The finish underneath will be smooth, slightly glossy plastic.
3. 3Avoid acetone, which attacks ABS itself rather than just the coating.