Missing ingredient in most DIY Mod Podge coasters instructions: "Envirotex" to waterproof them!! This blog explains (wonderfully) exactly how to use it!!! :) Glad I read this before I tried to make mine!
Rainbow Roses Get white of cream colored long stem roses. (Carnations work well too). Cut the stem according to the picture, you will then place 4 glasses of food color dyed water together. Put one piece of stem per color and allow the flower to soak up different colors.