COVID tests that people are shoving up their noses have micro beads of super absorbent polymers. So if you're blowing white snot it's because someone has smoked the drugs around you that cause you to expel the beads through your perivascular system. This was someone's idea of a sick joke because people who test for illness are "babies".
I recently saw some people wearing masks that weren't Japanese. I suspect they were suffering from both super absorbent polymer and nematode infection.