UNDER COVER NAIL VARNISH

Check out this article about a nail varnish that has been developed to detect when it is in contact with drugs... 

Date rape nail varnish created. A group of students from the US have created a beauty product that could help put a stop to the use of date rape drugs. The clever product called 'undercover color' is a nail varnish that changes colour when it comes into contact with drugs such as rohypnol, xanax and GHB.
The idea behind 'undercover color' is that if a woman is wearing the polish she can simply dip her finger into her drink to test it, and if the polish changes colour this will indicate that the drink has been spiked.