How to make hidden fire text on paper with saltpeter

Want to hide secret messages, but not with the usual invisible ink? Try something new... try fire!

This video tutorial will show you how to make hidden fire text on paper with saltpeter. You don't need the typical sympathetic ink to encode text on paper, you can use this attractive burning method, where the text is literally burnt into the paper.

To prepare this fire text trick, you'll need a sheet of paper, hot water, a thin paintbrush, a candle, cork, needle or pin, scissors, and potassium nitrate (KNO3, also known as salt peter), which is an ingredient used to make gun powder or flash powder, and is also used in fertilizer and for food preservation processes.