I have cotton socks, and they are really ruff to wear, and I stopped wearing them when I started to suspect that they were causing chaffing on parts of my feet.
Are there ways to make them softer, are my socks bad, do I only have the choice of polyester socks???
Washing in hard water can make cotton feel rougher.
Also when cotton is damp, like if you sweat much, it tends to be abrasive. That is why hikers say ‘cotton kills’ and recommend you stay away from it in favor of wool or synthetic ‘technical’ fabrics.
If they harden up because of hard water (for example water with a high lime content). Try to put them in a bucket with water and two big scopes of citric acid powder 4h to 12h before washing them. You can get citric acid almost anywhere online (ebay, Amazon etc.) This should soften them.
You can also use citric acid as a washing powder replacement if you don’t look for deep cleaning but softening your cotton cloth, but don’t use to much of it or too often because it can and will attack the metal parts of the washing machine.
But usually the the motor will die before serious damaged is caused as long you don’t overdo it.