Petro Canada 2010 Olympic Collector Cards.

The resin on the reverse of the 3 coins is coloured yellow for the theme of the coins is "Golden Moments". The actual coin is of regular colour.

to the Community, Nicolas F!

Not a 2004 poppy, it's a 2005 bookmark coin/item. The coin is not free in a holder, it's embedded in a lump of plastic resin, a real challenge to remove the coin from the plastic without damaging the red paint. I have/had two, one I tried to remove unsuccessfully (the paint was gone and the coin was silvery coloured, I don't know if it was the coin or the resin that was golden coloured the chemicals I used disolved everything except the metal) and the other has the golden appearance. Both had the golden colour the day I bought them almost twenty years ago.

PS Like mice45 I thought the golden colour was intentional.

Nicolas F, these are very nice Canadian hockey tokens...
. . . Go Rangers!

Another yellow-coloured coin is 2008 25 cent Poppy in the bookmark.
The colour on all those coins was there from day one. It is not toning.
If cannot be caused by the red paint because the paint is actually a strong enamel that requires a pure acetone to dissolve and, if it was the paint diffusion, there would be uneven toning like a halo.
You can look at the coins in the profile and see that the resin is coloured all the way through.
Note that resin is on the reverse only. The obverse side is a semi-hard transparent plastic.
I guess the manufacturing involves thermal processing because when you remove the resin there is a clear relief imprint on the resin.
Btw, the way I removed the resin and the plastic is by heating the coin to 80-100 degree C. It became soft and could be removed without taking off the paint.
It is still an unsafe method - it was a hot coin that I held with tweezers and I scratched my coin in the process.

Several years ago, I worked for a plastics machining firm. Some resins and plastics would turn yellowish due to age (out gassing), heat and/or ultraviolet exposure.

My memory about the Petro Canada Sport Card releases and the Golden Moments releases is very fuzzy so beware. The way I remember it was Canadian Coin News or the Canadian Mint did announce that there was going to be three gold coins released to commemorate the gold medals won by Canada. It seemed like they were talking about producing gold coloured coins for everyone to enjoy but then it ended up what they were referring to were actual real gold coins. The fact that these three specific Petro coins have toned a gold colour is just a lucky and amazing coincidence.

Nicolas F the same thing happened to my Petro coins. I bought them when they were normal only for them to tone while in storage. I have a theory for you why it's only these three coins that toned and why it's only on one side.

The mint has used different techniques to apply colour to coins and on these coins I believe it's possible that one technique similar to plating was used to apply the red ink to the coins with the very thin red line that highlights the maple leaf and a different technique like lasers and chemicals was use to apply the red ink to the coins with the maple leaf that's completely filled with colour. If you look at the close up pictures posted by prefix-kix the one with the thin red line shows the plating coming off the coin and the picture of the colour filled maple leaf shows horizontal lines probably caused by lasers and chemicals and that's what's causing the reaction to make the three coins tone inside their packaging. I don't know anything it's just a theory. Plus prefix-kix posted pictures of two coins with gobs of resin on the obverse and there's no toning around it.