>>9532527The reason old toys become sticky is because plasticizer leaks out of them. Normally this isn't much of an issue unless it's a softer plastic. I have toys from back in the 90s that are still aren't sticky. However, if a toy isn't able to "breathe" because it's still in it's original packaging, the plasticizer has nowhere to go when it leaks. So it coats the figure, making it sticky.
So really, it's worse to leave your stuff in the packaging. I'm sure some of those older figures might be a little tacky if you were to crack them open.
