left: salt sweater + 5 times washed patch ~ right: red and cream crenelle sweater + once washed patch
I'm happy to say (after testing numerous sweaters) that it's safe + cool to hand-wash the be-patched sweaters. Hand-washing is pretty awesome. Not only is it nice and gentle on the natural fibers, but the sweaters get better and better with each washing. With each washing, the merino/cotton sweaters are softer + drape better and the veg-tanned leather butters up, becomes more flexible and gets a pebbled texture. I'm a big fan of anything that gets better with wash and wear, and the sweaters certainly do.
I'm working on a sweater care page, with (hopefully) a photographed step-by-step hand-washing tutorial. Keep an eye out for it in the next couple weeks.