FSV.2 is coated with fog and scratch-resistant coatings to mitigate fogging and minor scratches on the shield’s surface.
You can use alcohol or water and soap to clean THE OUTSIDE part of your FSV as it is the only part that is exposed to outside particles. There is NO NEED TO CLEAN THE INNER PART. DO NOT use alcohol, soap, water or any cloth to clean the INNER part of the FACE LENS to maintain the anti-fog coating.
Anti-fog coating eventually wears off overtime but you can use any anti-fog spray or remedies to restore it's anti-fog properties.