I wash my ropes every year in the washing machine. 30 degrees Centigrade and normal washing powder. To save yourself time, indeed put the ropes in a bag. Otherwise one huge knot will be the result. No matter how you did put the ropes in.
I never dry them in the dryer. Too hot to me. I hang the ropes loosely to dry. So when it rains outside the whole living room is occupied
You will feel the difference after washing immediately. The ropes have lost their stubborness. I never discovered a disadvantage by washing.