Two things I have from my great grandmother... my middle name, and this antique quilt that she handmade. It has been at my parents house for a few decades. Since we now have our own house and have the room to bring all of our childhood things home, it has finally come to rest with me. I have no idea how long it has been since its been washed. Probably well over 10 years, which is way too long. Although washing a an heirloom quilt too often is probably way worse.
Fill your bathtub with lukewarm water.
Add about a cup of vinegar to gently brighten colors without damaging it.
Add a a little bit of a gentle detergent.
Swish it, dunk it, swirl it all around it the water for a little while (about 5-10 minutes) .
Then drain the water and fill the tub again with clean water, then drain it again. Do this until the water runs clear, no bubbles and no fogginess.
OR if you have a removable shower head...
You wont have to do as many steps of the filling and draining. Just turn the water on and VERY gently stand on the quilt to help with the rinsing process. Fill with clean water - squeeze the old water out.
Ring out the quilt as best as you can to get it damp, not still soaking.
Then, OUT of the direct sunlight, hang it on a line to dry (or if you don't have a clothes line then over some chairs or bar stools).
After some time outside the quilt was mostly all the way dry. The corner pieces were still a bit damp. I brought the quilt inside to rest of some chairs to finish up the drying process inside. You don't want an antique quilt to be out in the elements longer than it has to.
And there you have it, easy as pie and much safer than running it through the washing machine or dry cleaning.