Someone help me figure out this mystery

A few times over the last several years I've received a laptop back from an employee, either one that left the company or just received a new laptop and returned the old one, and there's something on it that I can't identify. It's a hard substance, almost like superglue, and usually presents as small droplets on the keyboard keys. I've tried to remove it with rubbing alcohol, goo gone, and I even tried scratching it with my leatherman knife. Nothing seems to be capable of getting this stuff off. I'm almost certain it's some kind of cosmetics, since the laptops are always returned by a woman, and often (I've noticed) smell like a makeup counter. That happens fairly often too, with or without the glue-like droplets. I've included a couple of pictures, does anyone know what this stuff is? I'm inclined to say it's actually just superglue, but I figure someone might have a better idea. https://imgur.com/a/OFJwC4d