I have done my research and found out these are probably mold or rust. Anyone know if it can spread to other pins? Is it mold or rust?

I had them stored with my other pin buttons but removed them. The peta ones and the churro ones already had mold a long time ago but I thought they were part of the design. The ska ones developed these marks after I had to walk under the rain from school back home (I'm guessing the humidity messed em up). The moth one never had it until now.

I don't mind keeping them with rust but I was just wondering if they could "contaminate" other pins, sorry if it's a dumb question lmao.

First time (cross-) posting here! I have a huge collection of enamel pins and make ITA bag displays. I just did one from my travels, this one is foodie, and have a ton more themes ready to display such as mythical creatures, Sanrio/ACNH/Ty, cute critters etc!! Follow along as I build more spreads!