Coin Storage - Long Term

I can't speak for the two items you point out, But I know for a fact that if you store copper Lincoln cents, in an ABS plastic tube for 15 years like I did, (I saved all my one cent coins in a 4" tube of ABS plastic until it was full, 15 years, about 10,000 + one cent coins.) the copper cents from 1973 through 1981, toned out to a very even and solid Gold appearance.
It's hard to capture the color of a group of coins, because of light angles. But they are a very distinct Gold color.

Dan