Pour the vodka into a sealable bottle or jar. Add 10 drops of red food coloring, 10 drops of blue food coloring, and 8 drops of green food coloring to the bottle.
Secure the lid on the bottle and shake to combine the colors. Store sealed in a cool dark place until you are ready to use.
Notes
You can make the black vodka ahead of time. Store the vodka in a sealable container in a cool place.