“The capsules of the Suunto compasses are made out of scratch resistant acrylic. As all outdoor gear, the capsule can collect scratches over time. Not a problem - the surface can be repaired with a soft cloth and acrylic polish.

Note that a Suunto compass must never be cleaned using alcoholic substances such as insect repellents. Alcohol will cause cracks in the acrylic material. Use only water and mild soap for everyday cleaning.”

https://www.suunto.com/hu-hu/Support/Compasses-feature-index/