If you have a huge makeup collection, you know it's nearly impossible to find enough space to keep everything. A shoe organizer on the back of your door offers space for all of your lipsticks, nail polishes, brushes, etc.
Like the idea - use a board to save the walls and maybe not Velcro since it'll get gross and isn't easily cleaned. Magnets or even small hole in cup to hang on a hook? Cars, Trucks and Teething Rings: Kids Toothbrush/Bathroom Fix