None of them will ever see the light of day so it shouldn't be an issue, straight into albums for all mine. I have the first coloured circulation coin, a 2004 Canadian poppy quarter. It is still the same as it was when it was released. However I am sure they will use cheaper paints in the future so they might fade. They do chip off.
The circulated $2 coins I have are all just jumbled together and exposed to light, not stored carefully at all. I guess that means they could at least chip.
THey will not fade. However if you place a coloured coin in acetone the colour will dissolve. One coronation coin, dissolved in acetone recently sold on eBay for $289! The item number no longer appears in ebay searches as it is over the seach days limit.
