Traditionally, silk is hand wash and dry clean only. Ours are of the highest quality so they are machine washable, but they are still silk and need as much care as we can give them.
ALWAYS use a ph neutral liquid detergent and/or fabric softener. Silk is a natural fibre and washing in a solution that’s too acidic or alkaline can cause the silk to harden in a single wash. If you can't find a detergent that specifies ph level then just go for one that specifies silk. Do not use bleach products.
Another important factor is water temperature. Even just slightly above 30 degrees Centigrade or 85 degrees Fahrenheit can change silk dramatically. The safest method if your machine doesn't specify exact heat settings is either cold or just one level above cold.
A delicates bag is optional, depending on your washing machine and whether or not it tends to grab items and tear them.
If you wish to maximise the life of your pillowcase, hand washing is the ultimate method.
The gentler you wash your slip™ pillowcase, the longer it will keep its sheen. The shinier it is, the better it will 'slip,' which is one of the benefits to its health and beauty qualities.
The same goes for drying your pillowcase, do not place in tumble dryer.
In other words, the better you care for your slip™ pure silk pillowcase, the better it will care for you.