Whatever I consider old and I don't like it, I wash again since all my fabric has been prewashed, I make into pet blankets or cut up into scraps for pet beds. If I see mold or smell mildew, I hose it down outside as the washer is filling up with soapy bleachy water or soapy vinegar. Then use it to make pet beds for the shelters. I also use a double rinse cycle. I have a rack I can use outside and hang some of the fabric to dry. Give it a quick press, sew them up and off to the pet shelter.