TIL In the 1930s, sequins were made of gelatin coated in lead paint, and could melt if they were touched or dissolved if wet.

https://www.smithsonianmag.com/arts-culture/a-history-of-sequins-from-king-tut-to-the-king-of-pop-8035/

https://www.reddit.com/r/todayilearned/comments/165yd5b/til_in_the_1930s_sequins_were_made_of_gelatin/