Put them in a pot of boiling water and dye some yarn!  That is exactly what I did and now I have 1600 yards of lace weight yarn in an amazing lavender color that is just waiting to be knitted up into something special.  This was such a totally cool thing to do that I have now found a new passion, Natural Fiber Dying.  Awesome!

Stats:

Knitpicks dye your own – 2 skeins Lace weight

1 quart semi frozen, definitely inedible blueberries from the back of the fridge

Soup pot, 1 gallon water (+or-), and 2 Cups vinegar

Bring water and berries to boil.  Cook for 1 hour.  Mash and strain out the blueberries.

Soak yarn in additional water and vinegar mixture, then place yarn and water/vinegar in soup pot with blueberry water.

“Cook” another hour or until water is clear and yarn has soaked up all the color desired.

Gently rinse yarn until the water runs clear and hang to dry.

*Do not stir the yarn too much while cooking.  It will felt!

Enjoy.