Scientists invent new technology to print invisible messages

Messages can only be seen under UV light and can be erased using a hairdryer

Forget lemon juice and hot irons, there is a new way to write and read invisible messages - and it can be used again and again.

The approach, developed by researchers in China, involves using water to print messages on paper coated with manganese-containing chemicals. The message, invisible to the naked eye, can be read by shining UV light on the paper.