Sure, you can shrink a cashmere sweater and it will look great. I've done it several times. It's all about technique. I'm going to show you how. There are two approaches depending on your goals [NOTE: don't do this with zippered sweaters. they will pucker since the zipper doesn't shrink]:
APPROACH #1 The No-Felt Approach
If you are dealing with a fine cashmere sweater that you want to continue using as a dress garment so you want to avoid felting and shrink in a controlled manner, here's the process. I have done this twice on thin dress sweaters in the $300-400 range (e.g., Zegna, John Varvatos). Made in italy stuff. This process will allow you to stretch it back out to some extent since it does not felt the sweater.Now, all this being said, it's important to note that the sweater will lose a touch of it's fuzzy feeling. That feeling is caused by extremely small fibers protruding from the surface of the sweater. Under bright light, they appear almost like the micro-hair on a woman's cheek. Once you heat wet fibers, they contract and that micro loft recedes into the sweater. It's still super soft, but the surface loft is mostly gone. It makes for a slightly more trim appearance. This method will maintain some stretch in the sweater and can be repeated periodically.
- Fill a spray bottle with water.
- Lay the sweater down in a tub or shower.
- Spray amply until the surface is covered EVENLY. About 1-2 oz of water (the core of the sweater will NOT be drenched). Fold the sweater once so the wet side is inside and press the sweater against itself like you were pressing a book closed. This forces the water into the fibers instead of sitting on the surface where it would evaporate without causing shrinkage. It is the process of water leaving the wool fibers that causes the shrinking.
- Do the same to the other side. another 1 oz. of water.
- Now, turn the sweater inside out GENTLY and do the same.
- Place in the dryer inside out. Alone.
- Not here's the trick, if you want to shrink it just a touch (i.e., 1/2 a size), then dry on cool air to dry for 20 mins.
- If you want to shrink it a full size, then put it on high heat for 20 mins. This assume your drier has a dampness sense which will cause it to reduce temperature toward the end of cycle. If yours doesn't adjust the heat based on dampness--or you don't know-- then put it on low heat and run for 20 mins. If it doesn't shrink your sweater enough, then re-spray and do it again. I have done expensive sweaters four times to tune it into the size I wanted and it didn't felt. I think the key here is to spray the sweater, but DONT DRENCH IT. Also, it helps to put it inside out in the dryer.
If some felting isn't an issue for you, then there's a method requiring less effort. This is the method I use for my sailing sweaters. I buy XL and shrink them down so they are snug and really thick and won't stretch if they get wet. This method will reduce the sweater by 1.5 sizes (e.g., From XL large to almost a medium) and it's a lot easier than method #1. That being said, you will lose the softness of the sweeter. It will NOT stretch back out. I would imagine lower heat would shrink less, but that is conjecture whereas everything else in my post is based on my own first-hand (empirical) knowledge.
- Boil a pot of water.
- Turn off the heat.
- Pull the sweater inside out.
- Drop the sweater into the water.
- push it down with a wooden spoon and stir just enough to ensure it is fully saturated with water. Try not to agitate it much. Cashmere fibers are delicate when wet.
- Remove sweater to a large sink. Be careful not to let it stretch as you do.
- Let it cool until you can touch it.
- Roll it up GENTLY. Don't twist.
- Press as much water out of it as you can. GENTLY.
- Dry it in the drier on med.