Count yourself lucky! If you have a handmade quilt, whether you’re the maker, or you hit the jackpot and received a quit as a gift, keeping it clean is a good idea. Easy answer to the question “how do I wash this quilt” would be to ask the maker.
I use all colorfast, high quality quilt fabric. I have a fair amount of confidence that when I wash my quilts in the machine, on a gentle cycle with a high volume of water, that I won’t have a color bleed over into another. I have never had this happen, and I wash my quilts whenever they seem to need a freshening up.
My personal procedure is to put my top load machine on the bulky setting, add a dash of Synthropol and wash. Things seem to come out great. Notice that my top loading machine doesn’t have one of those tall agitators, those tall agitators can damage a quilt. Front loading machines seem to work as well, at least I’ve heard. I have never had a top loading machine so I won’t be testifying to that info.
I then pop the quilt into the dryer on a medium setting with a fabric softener sheet and dry for 20 or so minutes. I like to take the quilt out of the dryer and hang it outside for a sunshine finish. I take all of my quilts out of the cupboard and hang them outside in the sun for a few hours, I think this keeps them fresh.
When you wash a quilt, there is usually some shrinkage of all the fabrics and battings. For most high quality quilt cottons, that shrinkage is a about 0/+5%. I’m including a downloadable pdf guide for quilt fabric care.
I do not wash my quilt fabrics before I cut and sew, I like the finish the fabrics contain, part of my touchy feely joy of quilting. I don’t worry about shrinkage after the quilt is made. I really like the way a washed quilt puckers just a little around the quilting stitches. There is something comforting about having that texture and I think it enhances the overall appearance.
Moda makes a few recommendations for what to do to prevent or correct fabric color bleeding. You can follow the guides they provide for other options that I haven’t covered.