25-Cent Invisible Ink/Pen (UV light visible)

Have you ever wanted to get one of those cool invisible ink pens from the store so you can write secret messages to your friends? Or maybe you need to use it to mark peoples hands for admission to a party. With this Instructable, you can easily do so, and do it for only 25¢!!

Step 1 Gather The Materials

There are very few materials needed for this Intstructable. These are listed below:

1 Highlighter (I got a pack of 4 different colors for only $1)
1 cup (plastic works best, so you don't have to worry about washing it out)
3 Tablespoons hot water
cotton swab
Pliers

Comments

[lukas_tek]

hey expertnoobz!
i need know one thing
the ink is visible under light of blue led?

[expertnoobz]

I'm not sure, i don't think it would be. I would test it out, but I don't have any blue LED's at this time.

[lukas_tek]

ok thanks
i will test it out when i go back to my house!
i'm travel and i still conected!

[expertnoobz]

Cool, let me know what happens!

[lukas_tek]

ok!

[batonas]

theres a black light leds, I would put one of those leds in a lighter so it wouldnt look that suspicious, it would be less bright but more stealthy.

heres a list of fuluorescent stuff by wikipedia

laundry detergents containing optical brighteners
soap
Body fluids (those are free)
sunscreen

[wolf996]

Body fluids (those are free) SICK!!!!!!!!!

[rimar2000]

Very interesting!