Only several common items, and you can write a invisible message.
In order to write a secret message, you need the following items: lemon, water, bowl, spoon, white, cotton swabs, as well as one of the most important is a heat source (such as heating, cooling large lamps, candles or hair dryer)
First, squeezing the lemon juice into bowl. Then add a little water, stir with a spoon.
Next, you can think what you want to write secret messages right.
The cotton swab dipped in lemonade, the lemonade dipped write down your top secret. Wait a few minutes, until the paper is completely dry. At this time, the paper has been almost could not see anything, you can give it to people who need to receive the message
Well, the secret message has been written out, but how to read it?
After the paper is completely dry, the secret message you wrote about heating. Depending on your choice of heat, the use of different heating methods. Heating time must be careful to avoid scalding yourself; if you use candles, do not get too close to the paper, the paper lit to avoid.
In poker, there are some invisible ink for playing cards, which is the back marked cards. You can use the invisible ink glasses to see the marks.