You’ve probably seen blacklights being used on TV or at clubs and bars, either used to investigate crime scenes or light up a club with some pretty spectacular results, but the fact that you can turn your own phone into one will probably leave you surprised, especially when you see how easy it is.
Using just two sharpies and some clear tape you too can have your own blacklight, enabling you solve important crimes from the comfort of your own home, such as who left the toilet in such a mess!
https://www.youtube.com/watch?v=UITRcw9t4zE
Here’s what you need.

Apply the tape over the flash and then colour it blue.


Apply a second layer of tape and then colour blue. Finally add a third layer but this time colour it purple.

Make sure all of the lights are off.

Then get ready to reveal something that you never wanted to see.

Source: youtube.com