Joe Webster, who lived in Houston for about a decade, was a research chemist for Shell. He had a huge book he wrote on chemical magic, that had everything in it from making colored flash paper, making flash paper that burned in different colors, clock reactions, you name it.
He submitted it to several different publishers, and they all turned him down. The liability was just too great.
So, there are methods, but because of the safety factors, you won't be able to get them. Also, most of the colored flame reactions used barium salts. They stink to high heaven and can be toxic.
Use a magic marker.
Bill Palmer, MIMC