How To Make Invisible Ink By Yourself At Home?

The funny thing is, invisible ink doesn’t necessarily have to be a sophisticated tool only used by a 007. Basically, all you need is something that chemically changes the paper enough to be read later on, as long as someone uses the right process. Here are three really simple forms of invisible ink that you can make at home!
When applied to paper, organic compounds leave behind enough of a residue that they heat up a little slower than the rest of the paper. To write a message in invisible ink, mix up a 50/50 solution of milk and water and write out your message. To decode your invisible message, just heat up the paper slowly. If you're in a rush and need to read the message quickly, just hold it up to a light bulb. If you see yourself as being very adventurous like Tom Sawyer, however, you should probably build a fire first and then use the open flame to make the invisible ink appear!
Another kind of organic invisible ink, lemon juice or really any other weak acids--most fruit juices will qualify—also leave behind a slight acidic residue on paper after drying. To make a very simple, organic kind of invisible ink, mix lemon juice 50/50 with water and write out your message using a paintbrush or Q-tip. To make your invisible ink appear, just heat the paper with a light bulb or stove element. Your friends should be able to decode your hidden message in no time!