Mine must be the Kostiner ones, I got them in a bunch of darkroom items one time. They are smooth so they won't leave a mark but I still am careful not to let the print slip out when I rarely use them. They will probably last for hundreds of years. If I were a young person I would probably wear a mask, fins and snorkel. 

These chemicals so far are the only things I have come across that I am allergic to. My opinion would be to play it safe, you only have one liver