These self zipping bags are ideal for protecting your jewelry from tarnishing. Each bag has been specially treated, they are non-abrasive, non-toxic, and environmentally friendly. Both sides of the bag is treated and is opaque. When the bag is ready to be changed you will notice the copper side will turn black. Bags will protect for up to 3 years after opened, unopened bags can be stored for up to 5 years. Make sure your jewelry or metal pieces are clean, dry and fingerprint ************************************************************* before placing in bag.