No scientifically special method that I know of. I just place them in a thicker plastic zip lock with a couple of air holes punched in them for air circulation. The bag just keeps them from rubbing against each other and getting scratched when I search through them. I keep them in a heated and air conditioned room so the humidity and temperature is relatively stable and they have done quite well over the years. Some of the Grips I have are over 100 years old! None have cracked, warped or changed that I can tell.