The hair should be kept moisturized and protected from the elements, including the pillow you sleep on at night. If possible, try sleeping on an African head rest. If you cannot, then you must cover your hair with a silk or satin scarf at night. If you find that your cornrows are tight and unfomfortable, have them unbraided immediately.
To wash your hair with cornrows in, place a stocking cap over all of the braids, and then press a mixture of water and shampoo through them with your fingers. Usually this will be one or two tablespoons of shampoo per liter of water.
After this, rinse the hair with the stocking cap still on, with clear water using a shower massager or “waterpick”. Try to get the water to flow under the braids as well as you can.
After this, use a leave in conditioner and perhaps a little hair spray or a moisturizing spray gel to refresh the holding product.