Dirt can hasten the deterioration of old fabric. Don't take an older quilt to the commercial dry cleaners, however. Chemical treatments and tumbling around in a drum will cause friction that can harm fabric and delicate stitching. Some experts recommend gently vacuuming with a soft brush attachment at a low setting, first placing over the quilt a sheet of plastic canvas screen or nylon window-screen material. Place the brush against the screen, lift and move to next area working in rows across the quilt. Valda Whitman hand washes in the bathtub, using a gentle detergent. Avoid soaps that can leave a residue or anything with bleach. She carefully gathers up the wet quilt, wraps it in a towel and then runs it through the spin cycle only in the washer to remove the excess water. Then she lays it flat on a sheet laid over a bed. Others recommend air drying only — laying the quilt flat in an area away from direct sunlight.
If you have old quilts folded, occasionally unfold them and refold in a different way. If left in the same fold for extended periods, folds can create cracks.
Keep them out of direct sunlight, which can fade and damage old fabric.
Never store old quilts in plastic tubs or blanket bags. Although it seems like a good idea to keep them dry, the airtight environment can lead to mold or rust if moisture collects inside. Instead, store them in pillowcases, which will protect them from dust while also allowing the fabric to breath. If it's really old and valuable, consider storing in acid-free paper to prevent the material from discoloring.