Washing My Pillows

I recently saw an article that talked about the amount of dust and dust mites that inhabit our pillows.  It was estimated that the weight of a three-year old pillow would be almost 50% dust and dander.  With my allergies to dust mites leaving me prone to perpetual stuffiness, I decided to wash my pillows in the washing machine.  I have allergy-reducing covers on all of the pillows as well, but have not washed them in a year, which probably renders them useless.  Hopefully, this will help.