Ok...I have made my gum paste flowers and they are stored in air tight containers until I need them. What is recommended to make them shiny? They seem so dull once they dry.

How about dusting them with some luster dust?

That is mixed with an extract or vodka, correct? Does that need to be done right when I am decorating the cake or can it be done ahead of time and stored in the airtight container? Do you brush it on?

Steaming it will also give it that shiny effect. You can hover it on top of a pot of boiling water.