Yellow decals

I got this very old kit off Ebay and the decals are yellowed. How can I make it new again?

Hey hou,
I have heard to put the decal sheet(s) into direct sun light. To do this just tack up to the window(attach tape to the back ofcourse) that recieves the most sun light.
The sun basically bleaches the yellow which brings it back to its original condition.
Every so often check on the decals to see how they are doing?? The time it will take to bring the true colors back depends on how yellowed they are.
If your wondering will it also bleach/fade the decals itself, I have never heard of that happening before.
Flaps up, Mike

Hang them in the window is right but I would put them in a freezer stoage bag taped to the window. Also once the yellowing is gone you have to use the decals or the yellowing will come back.

Hey Tiger,
I heard that if you put them in the storage bag, it may/could produce moisture.
If it did produce moisture, when it came time to take out the decal, it may stick to the bag and theres a possibility it may ruin the sheet.
Thats why eveytime I hear about this process, nobody ever mentions about putting the decal sheet in a storage bag[?][?][:p].
It may work but I’d test it out first before you put the whole sheet in[;)](use a part of a decal that you wont use or need).
Flaps up, Mike