I agree with the guess that these are pre-1930s fabrics. If the quilt is in overall good condition and is very dirty, you can soak it in a bathtub with Woolite or Fels Naptha soaps, gently squishing the water through the quilt with your hands. Then empty out the water and do it again if needed, and rinse it in the same way. Gently roll it to get excess water out - Don't Wring it!! Be careful how you handle the delicate fabrics when wet...the water weight itself could damage the quilt. You can roll it with towels to get it a little dryer, then lay it completely flat to dry, preferably indoors.
You have a wonderful treasure there. You are a lucky girl!!