Hello,
I'm looking for a chemical or a product that would be hidden in a th**b t*p and would change the color of a fire. preferably green, but any color would do.
I thought of copper sulfate or boric acid, but both are classified as toxic for the skin.
do you know something I could use?
thanks a lot!

Borax will change fire to green. More importantly, how do you plan to control the fire?

I am surprised that you did not use the Internet for your questions. I simply found the answer by using Google. Then there are kits sold on Amazon to change fire color.

Warning, fine powder burns very easily, and will flare up and burn very hot, and will backtrack to your TT and set you on fire.

Read this to begin with: https://www.wikihow.com/Make-Colored-Fire