Took some of my old figures out of storage but some have this waxy coating?

Took some of my old figures out of storage but some have this waxy coating?

As the title says, a handful of my figures have this waxy coating on them. It wipes off with a clorox wipe just fine. Is there any reason this happens, or does it just happen with this type of plastic?

u/NightBrix — 1 day ago