me. I am waaaay over 8 years old. And its lots of fun.
If you are reading a homemade invisable ink, such as..lemon juice..simply hold it to a light bulb.
you dont have to look at it while it is showing up, if your worried about your eyesight.
If your using the cool presto chango markers you can get, you need to color over it with thr other marker.
If your using ink from a detective/secret angetn/spy kit you got ordering off the back of a cereal box, well, it should have come with directions. Otherwise, its a lousy kit and ask for your money back!!