Authentic super-secret spy gear is expensive and hard to come by. However, you can use simple spy secrets to make spy stuff at home. Help your kids compile a spy kit for play, or make one for yourself, as part of a costume. Use the spy gear to solve a secret mystery, or just for fun.
Put a sprinkle of starch powder onto a porcelain dish.
Hold a second, heat-safe porcelain dish over a candle flame. Allow the soot from the flame to collect on the dish.
Scrape the soot off the dish with a knife and mix it with the starch powder to create fingerprint powder.
Dust the powder over fingerprints to reveal them.
Cover the dusted fingerprint with clear tape and lift it up gently to remove the print.
Find a book with a hard cover that you don’t mind cutting up.
Pick a page near the front of the book, but not directly at the front, to open the book to.
Use an X-acto knife or a box cutter to begin cutting the pages after the page you turned to. Begin on the right-hand page and cut a square out from the interior about 1 inch from each edge of the page.
Continue cutting down through the pages until your hole is deep enough. Do not go all the way through to the end of the book.
Store items in the empty space you cut out.
Use a toothpick or the pointy end of a feather as your pen, and lemon juice as your ink.
Write out your message in the lemon juice. When the juice dries, your message will be invisible.
Reveal the message by holding a hair dryer over it or holding the area over a candle flame. Make sure to keep the paper far enough from the flame so it is heated, but not burnt.