Make your own colored beads
Here is an original tip to make wooden beads of various colors. Using raw wooden beads, you can now make colored beads to suit your needs or in every color of the rainbow.  
You will need:
The steps:
  1. Insert a toothpick (or two if the hole of the bead is large) to prevent the bead from turning while you paint it 
  2. Apply the nail polish all around bead
  3. Place beads on knitting needles to dry
  4. Let them dry 30-60 minutes
Now you only need to apply a second coat of nail polish and let it dry all night. 
Voilà!  Now you know how to use your leftovers of nail polish. I tested their durability by wearing the beads for several days, to see if they remain nice and shiny. 
I guess the durability is directly related to the quality of the nail polish, but it seems very durable to me. They look very high quality, without any possible scratch on my side.
Feel free to share your experiments with this project!