As someone who has usually around 5 mascaras going at one time, this tip sounds perfect!
You know how you never get all of the mascara out of the tube before it dries out? I saw on Pinterest that you can add 4-5 drops of saline solution, insert the wand, stir it up and tah-dah! You can do this 3 or 4 times or until you use up all of the mascara.
Let me know if you give this a try as I have yet to do it and you may beat me to it. I would love to hear your comments on this new found money saver!