What's the least painful way to wash a heated blanket?

Check the label first, most newer ones are machine washable but not all. - unplug it and disconnect the controller cord, the controller never gets wet - gentle cycle, cool or warm, a mild detergent, no bleach or fabric softener - keep the cycle short, the wires inside don't like a long spin - don't wring it. dry it flat over a couple of lines or an airer, or tumble on low for a few minutes and finish it off flat Make sure it's completely dry before you plug it back in. And never dry clean one, the solvents damage the wiring.