Clean your face using the rubbing alcohol and paper towels, making sure to wipe down all areas of skin the mask will be in contact with. The purpose of this is to remove not only dirt, which would be removed through normal washing, but as much of the oils on the surface of your skin as possible. Do the same to the inside of the mask, as it may have dust or powder applied. Both the oils and the powder will prevent the mask from sticking to your face properly. Allow the alcohol to evaporate completely from both surfaces.
Apply spirit gum to the inside of the mask and wait for it to become tacky. To test this, lightly dab the spirit gum with your little finger. If the gum sticks to your finger and forms strings when you pull it away, it is ready to be applied. Applying the mask before the spirit gum gets to this point will cause it not to stick properly, making it likely to need touching up later. Remove the spirit gum from your finger by applying rubbing alcohol.
Place the mask on your face and gently press, making sure to push all the spirit gum against your skin. Do this very carefully, as the mask will immediately stick to your skin and repositioning it will not be possible without removing the gum.
Apply prosthetic makeup to the mask and your skin to blend them together or create other visual effects if necessary.
Remove the mask by by applying rubbing alcohol. Soak a paper towel with it and rub it gently along the edges of the mask, gradually pulling the mask away from your skin and applying more alcohol at the point of connection until the whole mask comes away. Do not pull forcefully on the mask, as you may damage your skin and the mask will tear long before the spirit gum comes away.