How are weighted blankets washed?
I have to handwash everything, so only purchase what can be handwashed most easily. I just use multiple throw-sized blankets, and wash them one at a time.
Whenever I move, I order a centrifuge from Amazon or directly from the manufacturer if I can afford it.
Ninja 3200 RPM Portable Centrifugal Spin Dryer with High Tech Suspension System
When I move, if none of my neighbors want it, I can usually dispose of it in a way that does not cost me anything.
Wringing the items out is the worst part of handwashing, and if you don't have a place to hang them outside, a centrifuge vastly reduces the amount of humidity released into your home, as well as vastly reducing the time it takes to dry. You can iron an item dry as soon as it comes out of the centrifuge.
I cannot image that I could hand-wash a weighted blanket.
I use a heating pad as a partial electric blanket, when I cannot afford to heat the entire room or home.