I’ve deliberately shrunk cashmere sweaters several times for my own use, as well as accidentally shrunk a few, so I can speak to some of this.
(For the curious, it’s pretty easy to find huge men’s cashmere sweaters cheaply on eBay – people seem to like to give men expensive sweaters as gifts whether those men are sweater-wearers or not – and shrink them three or four sizes by washing in hot water and drying in a hot dryer, leaving you with an extra-warm, extra soft, clean, cheap sweater. You can also do this with regular wool – with the conditioner treatment I describe below, it gets a lot softer. I wear a women’s large, so starting with a men’s XL or XXL is just right for me. Women’s styles are more flattering, but much harder to score for cheap.)
It will never be as big as it was, whatever you do. It is possible to get it a little bigger than it* is,* but you will have to re-stretch it aggressively (and do so again every time you wash it). It will always have a different look than it did – less regular, more sort of melted-looking. It will still be sweater-shaped, though, and wearable. There’s a chance that it might end up too bunchy in the underarms for comfort.
If you want to try anyway, go buy a big bottle of cheap hair conditioner. Make sure you don’t mind its scent, as the sweater will smell a little bit like it forever after. Draw up a bucket of room-temp water. Pour the whole bottle of conditioner in there and swish it around to dissolve. Put in the sweater; squeeze it (gently) and hold it under until it’s good and saturated and doesn’t just float on top. Leave it there soaking in the bucket for three days.
Take it out and rinse it in cold water. Be gentle – remember that the more you agitate, the more the fibers tighten up. Squeeze the water out, but don’t wring it. Wrap it in dry towels and stand on it to get more water out.
Now stretch the heck out of it. Pull on it, stretching slowly but very firmly. It should be a real workout for you (I always feel sore for a few days after doing a batch of these). Alternate stretching length and width. Most sweaters shrink more in one direction or the other – it seems like the body usually gets a lot shorter but not narrower, while the sleeves do the opposite – stretching in one direction gets you slack that you can then pull the opposite way, so do both. Take your time.
Hang the sweater on a good big plastic suit hanger – not the cheap kind you get by the dozen; the kind more shaped like actual shoulders that they give you when you buy an expensive coat or suit at retail – to dry. Stuff plastic bottles down the sleeves to block them wider (one-liter plastic soda bottles are perfect). Visit the sweater often while it’s drying and pull on it some more.
I’ve been able to get back about a size this way.
I’ve had no luck wearing sweaters to block them while drying, BTW, as it takes wool so long to dry.
