Here is two alternative ways in egg's decoration: Hard cooked eggs or empty eggshells.
I am decorating empty eggshells. It is easy to make an eggshell empty. First, wash the egg. Prick with a long needle or with sharp nailscissors to make a small hole in the both ends of the egg. Stick the needle or something like a needle into the yolk to break it inside. Bowl until the contents come out.
To remove egg dreg from the inside of the eggshell:
Fill the bowl with warm water and with a spoonful detergent . Submerge each shell to fill it with the water in which the detergent was melted and shake. Let them sit for five minutes, then drain the water. Empty each eggshell and dry. You can preserve these eggshells for a longer time by processing cleanup.
Before painting, I clean eggshells in lukewarm water with the vinegar.