I got some 'thin' solid fabrics in a batch of vintage fabrics I bought on eBay. I was worried about using them, so went ahead and pre-washed some, and they seemed OK after washing so I have used some in miscellaneous quilting projects and so far so good. However, I don't think I would risk them on "important' quilts like wedding gift quilts, etc. It is hard to know if they will hold up as long over time. Frankly if you are worried about them, I would trust your gut and not use them--donate them to someone else that would like to have them and not continue the worries!