At the risk of sounding uncouth, what is a pillowcase "liner"?

I have had very nice fabric fray like crazy and very cheap fabric hold up well.
One of the first quilts I did was made from this gorgeous decorator fabric that I should have used wider seams on. Since I didn't and it is already partially hand quilted (one of many UFOs) I am now very carefully quilting beside the ditch in the sashing catching in each seam allowance so that the likelihood of fraying is reduced. I'm hoping this will take care of the problem. Think this one will end up as a display only quilt anyway.

I had some black solid fabric, bought in a Lancaster quilt shop during a trip to the USA, fray so badly when the top was washed that the top was in danger of falling apart. Very disappointing. I used what was left to make the inner layer of cat beds. There was simply no point in endangering other quilts with it.

Unless I have an iron-clad reason to buy looser-woven fabric, I avoid it like the plague.

Trash... cheap fraying fabrics shouldn't be used in quilts. It will just fray in your quilt.

Its best to buy good quality fabric for quilting.

Fraying Fabric
 

I have had "good" fabric not cut properly when purchased. Then when I cut it into strips I notice all the fraying on both sides. The strips I continue with and handle as little as possible. If I notice this before cutting, sometimes I take the time to 'straighten' the fabric and cut along the warp (?). Then you lose some of your fabric as it can be as much as 2-3" off grain. If it is a block that I'm using as a background for applique, I use Fray Check. As someone else noted...it is wonderful for this.

I make play houses out of the nylon and instead of fray check, I use fray BLOCK because it leaves a softer edge.

I agree with BJChad: zig-zag the offending fabric.

Well, first of all, if is fraying so badly you can hardly handle it, why would you want it in a quilt? I'd get rid of it and use something with more structural ingerity!

First of all, wash it......that may help you make up your mind....I had some that badly frayed. I washed it and it came out a wrinkled mess. It went in the trash!

I too do the zigzag stitch. And I find that it's not necessarily cheap or thin fabric that frays, just some seems to for some reason, especially flannels.