I know this should probably be posted in a chemistry exchange, but I figured the parts are pretty standard electronics equipment that the question might be more relevant here.
So a couple of breadboards had been lying in a box with a rubbered aligator wire sandwitched between. They've been there for maybe a month untouched. No other chemical or electricity has been present and only ambient heat (hot summer but 30°C tops here in Sweden). I'm pretty shocked that the plastic of these two different styles of breadboards both got so messed up simply by touching this rubber:
Should I be concerned? Is either the plastic or the rubber dangerous to me?
Best Answer
"Melts" isn't the correct term here -- that would involve heat.
The vinyl boot on the alligator clip contains a solvent called a plasticizer that helps keep it pliable. However, it is volatile and its outgassing has also affected the plastic used in the breadboards.
The solvent is a volatile organic compound, and is probably dangerous if concentrated sufficiently, but at the low rate that it outgasses in a reasonably ventilated space, it is generally considered safe.