There are many ways to color a fire, but the most effective is to add salt. You can also burn color-printed materials, but these will give off toxic fumes and cinders that can ignite nearby objects. Likewise, burning plastic can release toxic and carcinogenic chemicals. To avoid these hazards, burn colored-print paper safely, but be careful when burning it. Use gloves and follow manufacturer directions carefully. In case of accidents, do not burn yourself or others..