Any Sure fire way of storing pennys to prevent contamination?

[knsgee]

Anybody know a fool proof method of storing copper pennys to prevent corrosion. The coin in question is a Canadian 2007 one cent coin and so far has avoided any contamination but a large number of similar coins have been tarnished even though they were housed in the same manner, commercial 2x2 coin holders and the plastic sleeves designed for them. It seems to me they changed the material used to make the 2x2's and I was wondering if that is the source oi the considerable amount of contamination the other coins are being affected by.

[benrocky]

Hello, the only way to avoid contamination is to seal the coin so it would completely sealed, no air.

PCCS