What should I put inside clear gl Christmas ornament favours?

You could put green and red christmas M&M's in them that they could enjoy that day, but for something to last i would say maybe some green, red, white, gold (whichever colors you're using in the wedding) confetti string to place in them. And if you wanted you could find the glue that dries clear and rub it along the inside and put just a little bit of colored glitter and shake it around to have a sheer color that sparkles in the ornament. i think all of these ideas would be cute!