Regarding how to wash silk products. What happens if I wash them in a washing machine?

As the owner of a brand of nightcaps made from silk, I will explain how to wash silk fabrics based on my actual experience washing silk products.

Even among silk materials, the amount of silk in the fabric and the combination of materials vary widely.

This article will mainly discuss silk-cotton fabric and 100% silk fabric.

Washing 100% Silk Fabric

Leaving aside whether all products are like this, the washing labels for products using silk fabric are basically as follows:

• Hand wash
• Do not bleach
• Do not tumble dry
• Dry flat in the shade
• Do not iron
• Do not dry clean
• Use neutral detergent

In fact, as shown in the picture, the nightcaps I produce have a washing label on their packaging.

However, when you're told "No, no," it's not clear what you should do.

So, a simple interpretation of these washing instructions is as follows:

Use a neutral detergent (delicate wash detergent), hand wash without using a washing machine, then reshape and air dry in the shade.

There are many other websites that provide detailed instructions on how to hand wash silk, so I'll defer to them for the specifics, but a very simple explanation is as follows:

• Hand Washing Method
• Soak the item you want to wash in lukewarm water at 20 degrees Celsius, add delicate wash detergent, and wash by pressing your palms up and down, then rinse gently.
  *Do not rub or wring.

What happens if you machine wash 100% silk fabric?

But you know, hand washing, to put it simply, takes time and is a hassle.

So, I tried washing it in the washing machine using the hand-wash cycle with delicate wash detergent and a laundry net. *I didn't use a dryer because it shrinks.

As a result, it gets wrinkled, but it's not unwearable, and my impression is, "Well, if I stretch it out, it'll probably be fine," which is within an acceptable range.
Modern delicate wash detergents are truly amazing!

Gradually getting bolder, I finally forgot to set the washing machine to "hand wash mode" and even used it without delicate wash detergent (but still used a laundry net).
*Please do not imitate this.

And what do you know? It became extremely wrinkled, or rather, stiff? It wasn't unwearable, but I can't deny that the smooth texture and luster were sacrificed.

Where did the goodness of silk go?

My Recommended Time-Efficient Washing Method for 100% Silk Items, by Item

What I'm about to write is just my personal opinion, so feel free to skip it if you're not interested, but I'll share the washing method I arrived at after trying to hand wash and machine wash 100% silk items.

For silk shirts and other items where luster is key, hand wash and iron (do not use a steam iron; use a pressing cloth and iron at low temperature for a short time).
For items that are not worn outside, such as nightcaps, machine wash on the hand-wash cycle with delicate wash detergent and a laundry net, reshape, and air dry in the shade. This is fine.

Washing 50% Silk, 50% Cotton Fabric

Next, I will introduce how to wash fabric made of half silk and half cotton.

Incidentally, this silk-cotton fabric is used in all nightcaps, except for the Towari series, from ITSUKI, the nightcap brand I operate.

The washing instructions will likely be the same as for 100% silk fabric, usually as follows:

• Hand wash
• Do not bleach
• Do not tumble dry
• Dry flat in the shade
• Do not iron
• Do not dry clean
• Use neutral detergent

The washing method to prevent fabric damage is also the same as for 100% silk fabric, as follows:

Use a neutral detergent (delicate wash detergent), hand wash without using a washing machine, then reshape and air dry in the shade.

• Hand Washing Method
• Soak the item you want to wash in lukewarm water at 20 degrees Celsius, add delicate wash detergent, and wash by pressing your palms up and down, then rinse gently.
  *Do not rub or wring.

In other words, the washing method is the same for 100% silk fabric, whether it contains cotton or not.

What happens if you machine wash silk-cotton fabric?

Now, in my personal opinion, the true value of silk-cotton fabric shines through when it's machine-washed.

To be honest, I put silk-cotton nightcaps in a laundry net and wash them with other laundry in the washing machine. I don't use the hand-wash cycle, nor do I use delicate wash detergent.

*Absolutely avoid the dryer, as it will shrink!
*Please proceed at your own risk.

If you're asking if this washing method keeps the fabric in the best condition, the answer is, of course, no. For those who seek better luster and texture, the only path remaining is "hand washing."

However, the good thing about silk-cotton fabric is that even with such a sloppy washing method, it doesn't become "stiff," and the result is "pretty acceptable."
(It goes without saying that using a delicate wash detergent would further improve the texture.)

Summary

To summarize what I've written so far, it's as follows:

• For 100% silk or silk-cotton, if texture and luster are prioritized:
  → Delicate wash detergent + 20-degree water + gentle pressing (no rubbing or wringing) + gentle rinsing + reshaping and air drying in the shade
  → Recommended for silk shirts, expensive underwear, etc.
• For 100% silk or silk-cotton, if you want to save time by using a washing machine:
  → Washing machine + hand-wash cycle + delicate wash detergent + laundry net + reshaping and air drying in the shade
  → Recommended for items not worn in public, such as nightcaps
• For the easiest way to wash silk-cotton with acceptable results (not recommended for 100% silk fabric):
  → Washing machine + laundry net + reshaping and air drying in the shade
  → Recommended for those who prioritize ease of use over the resulting texture
• Prohibited in all patterns:
  → Use of a dryer

Lastly, let me say this: no matter what, following the washing instructions is the best for your clothes.