I had the incredible fortune of buying several vintage quilts for only $10 each. I don't think the seller knew their worth?! Usually these quality of vintage quilts go for a couple hundred dollars or more.
Anyway, they all had that old musty smell to them. They smelled of dust and damp, like an old attic. And I really wanted to keep them out with my collection of other vintage quilts. But with the smell, I just wouldn't be able to! So, I got to work. And they are now smelling fresh and lovely! This method can be used for just about any fabric that needs to be rid of unwanted "old" smells. If it is dry clean only, then DON"T do this, take it to a professional. But if it is a washable fabric, then by all means give it a whirl! For especially stinky fabrics it may take 2 or 3 times through the process to really get the ick out.
Fill the bathtub with cool (not cold or warm) water.
Add about an 1/8th of a cup of a mild detergent, such as Ivory or Dreft, and slowly swirl it into the water to disperse it well.
Add about 1/8th cup of Arm & Hammer washing soda and dissolve by stirring.
Add in 1 cup of vinegar. (The smell will dissipate, I promise!)
Gently lay the quilt, blanket, etc. into the water. Using your hands, softly press it into the water, pressing in different areas each time. Slowly turn it over to the other side and repeat. Let it sit for an hour or so.
Drain the water from the tub, and refill with cool plain water. Then repeat the process above with the quilt, pressing the suds out of it into the plain water. Repeat until the water is clear, and no more suds come out of the fabric.
Roll the quilt tightly while still in the tub to squeeze out excess water. Then take it outside into the sunshine and hang it to dry. Over a railing will do if you don't have a clothesline.
The combination of the vinegar, washing soda and the fresh air should remove the musty smell and leave it fresh and bright. The soap and washing soda will remove any dirt or dust that is keeping the odor in. And the washing soda will leave it nice and soft.