I wash my blankets with regular detergent in the washing machine, and throw them in the dryer on a regular setting, every year.  Spray them with waterproofing spray after (get it at Walmart, has a dayglo orange cap), and they're good to go every year.

image"Avoid loud and aggressive persons, they are vexations to the spirit." - Desiderata, Max Ehrman. 1926. image