After they are quilted and bound they should handle washing just fine. Cool water, gentle cycle or by hand swished in a bathtub. Mild quilt detergent. Tumble dried with medium or low heat. They will be beautiful. Washing is better than the harsh treatment of dry cleaning which they may be tempted to do if you label them to not wash. Dry cleaning is a horrible choice for cotton quilts, the dry cleaning chemicals can eat the fibers. Cottons generally launder well, become softer, lovelier with time. They shouldn't be laundered like bed sheets, often; but once or twice a year is fairly standard.