or does it just depend on the binder?
It's actually recommended to hand wash and air dry underworks binders. Don't know about the others though
I don't see why not. Just rinse it good and don't do a bunch of wringing because I think that could damage the material. I'm about to start hand washing mine because there is a tear in the side under the armhole. If I hadn't been so lazy and put it in the washer I would not have that problem :(
I can't see hand washing being harmful to any material, but there should be instructions with whatever binder you get. With underworks, it definitely works, though I think it's recommended that you not wring it. Also, hand washing mine didn't re-tighten it as well as machine washing it, but that can also be a good thing if you don't mind keeping the worn-in comfort over an extra centimetre or such of binding efficiency.
This guy on youtube describes how he washed a binder, before giving it to someone else. It is, perhaps, not what you'd do for regular use, but he does describe doing it by hand.
How to get and care for a binder, and Red Friday... (http://www.youtube.com/watch?v=xkBovAzEBBM#noexternalembed-ws)
He is one of my favorite youtubers, though he hasn't posted in a while.
You should watch this series of his about his effects of T, very informative and intelligent (1 of 3):
Things they don't tell you about T (http://www.youtube.com/watch?v=w3gpLkCY0Eo#noexternalembed-ws) 4.30 is great!