Step 1: Have you ever written a secret letter? If not, the time has come to learn how. You will need: a sheet of paper, a brush and a lemon. To read the letter you will need a candle.
Step 2: Squeeze some lemon juice onto a plate.
Step 3: Wet the brush with lemon juice and begin to write. Frequently moisten the brush with lemon juice.
Step 4: Allow the juice to dry.
Step 5: If the lemon writing is still visible, crumple the paper and it will appear clean.
Step 6: And now the most interesting part! (Warning: children should continue only with adult supervision). Light the candle and, having flattened the letter, pass it carefully over the flame. You will see, as though by magic, that the writing becomes visible. Be sure to not hold the paper too close to the flame or in one place for too long–you risk burning up your letter!
Step 7: The secret letter revealed!