Here are some tips from a dry cleaner on cleaning socks with bad dark staining: 1) Use builders like washing soda and borax to break up those metallic bonds. Add some to the drum of your washer, tamp some in directly, or even soak in water with builders to do a lot at once. 2) Ensure you are also using a detergent, odds are there’s quite a bit of body oil in there making them super sticky. 3) Hit it with oxygen bleach to whiten and brighten I hope this helps! #sockcleaning #laundry #laundrytips