None. They already glow.
Find out next time on Dragon Ball Z!
To get to the other side.
It takes 1 to screw it in, and 99 to tweet about it.
Both of them.
Because Chernobyl fallout.
Chernobyl fallout...
Obi-Wan: We'll be stealthy. *turns on huge, glowing laser sword*
Got to glow now!