I know fireworks use different chemicals to get different colors. This probably means combustion/oxidation of the various compounds, resulting in vapor phase gases. With fireworks, this might not be a problem, but if I have an indoor fireplace, are there any chemicals I can safely add in order to change the color? I think it would be awesome to have rainbow flames. I know different woods burn different colors, but finding wood is difficult. I can, however, attain chemicals.