You can mix superfine popcorn salt (about half a teaspoon per cup) into the alcohol and it will burn orange. Regular table salt doesn't dissolve very well in it.

It seems I heard that you can add borax (Twenty Mule Team borax from the laundry section is 11% borax) for some kind of color, but I don't remember what color, or if there were negative reasons not to do it.

This sounds like Blast's department to me!

Sue