Cashmere is unfortunately a quite fragile material due to the fact that it is precisely this fragility which is the source of its softness.
Cashmere socks are valuable, take care of them!
The fact remains that there exist methods for efficiently washing cashmere without destroying it.
Hot water and rubbing are the most ruthless enemies of cashmere socks (likewise for sweaters). Felting is the primary danger for cashmere socks.
How can felting be explained? The wool is made of scale-like fibers Under normal conditions the scales travel in the direction if the fiber. Under the effects of heat and humidity the scales open. Once the scales are open, the fibers no longer slide between one another. The rubbing, therefore, causes the fibers to intertwine instead of remaining combed. The thread, the fibers of which are intertwined, are shortened and elasticized. This is exactly the state of felted wool: shrunken and
with no elasticity. Wool fiber as seen under a microscope.
If there is no stain on your socks, there is no need to complicate matters. Putting a little cold water and soap on them, washing a bit, and rinsing abundantly is sufficient Afterwards, dry them by laying them flat.
If there are stains, appropriate products for each type of stain must be applied (mild household soap for the greasy stains, vinegar for wine…).