For a personal touch, stitch your mother and mother-in-law's initials onto vintage handkerchiefs and present them to the women before the ceremony.
Tautly secure an embroidery hoop around the part of the handkerchief you wish to monogram, then sketch the initials on with a disappearing-ink marker (depending on the one you use, the ink will disappear in 24 to 72 hours).
Need font and style inspiration? Just flip through an embroidery design book. Using your sketch as a guide, stitch over the letters with embroidery floss, then remove the hoop.