Fun Activities: Secret Spy Kit – Making and Decoding Hidden Messages

G1 has been asking for “invisible ink” ever since he read about using lemon juice to write hidden messages from one of Enid Blyton’s adventure books so when I stumbled on a Secret Spy Kit, I decided to get it for some secret message fun at home…

What’s in the Kit?

  • Code Book – that teaches kids various secret code methods, like the “Pig Pen” and “Morse Code”
  • Compass
  • Decoder Card – to reveal hidden messages
  • Code Torch – for sending morse code
  • Secret Marker Pens – invisible ink and revealer

The activities are pretty straight forward and easy to DIY if you have the time and patience for it.

Invisible Ink

There are two pens:

  • secret marker – for writing hidden messages
  • developer marker – for revealing the hidden message

Secret Spy Kit

You can also make your own “invisible ink” with lemon juice. To reveal the messages, warm the paper with a hairdryer, a candle, a desk lamp, or leave it under the sun for a while.

Decoder Card

Reveal hidden messages with a decoder card.

Secret Spy Kit

You can also make your own decoder card using red cellophane paper:

More about them here: Designing for Decoder Glasses, Print and Web.


Published by Shen-Li

SHEN-LI LEE is the author of “Brainchild: Secrets to Unlocking Your Child’s Potential”. She is also the founder of (a website on parenting, education, child development) and (a website on Right Brain Education, cognitive development, and maximising potentials). In her spare time, she blogs on Forty, Fit & Fed, and Back to Basics.

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

%d bloggers like this: