Tarnish On Silver Coins?

I have purchased a number of new mint silver coins over the past few years - silver eagles and Canadian maple leafs - and today I noticed that a few have started to tarnish, turning black in places, even though they appear to be sealed in their original mint plastic envelopes. What causes this? Does it effect the value? should I do anything about it? What is the best way to store these coins? They are currently in a safe - dry and dark.

Related posts:

  1. Invest in Collectible Silver Coins and Bars Bullion: Buy Like 5 Dollar Silver Maple Leaf Coins Invest in Collectible Silver Coins and Bars Bullion: Buy Like 5 Dollar Silver Maple Leaf Coins Silver has captivated people like myself for over 6,000 years. Around 700 BC, Mesopotamians...
  2. Silver coins and silver bullion Silver coins and silver bullion The silver market offers investors a variety of products. US pre-1965 90% silver coins, which were used as money until the mid-1960′s served both as...
  3. Silver bullion or coins? For less then 0 hundred dollars would you suggests silver bars, rounds, or something like American Silver Eagles or Canadian Maples? Is it safe to buy these from a website...
  4. Investing In Silver Coins, Silver Futures And Silver Stocks! Investing In Silver Coins, Silver Futures And Silver Stocks! Silver vs Gold? What is better as an investment. Many people are obviously going to say gold. But, to tell you...
  5. Silver bullion coins? what are other silver coins I can collect other than American Silver eagles and Canadian Maple leaf silver coins?...