I recently went to a retreat with the Clark County Quilters. One of the organizers led a class on selvage edge piecing and before you knew it, we were a pack of hungry wolves going through the enormous pile of selvages. I came away with a sack full of mostly green and blue selvage edges.
Since I have a bolt of black fabric, I decided to make half square triangles with one half done with selvage edges and other half black. I didn't actually cut half square triangles, though. I cut 8" squares of the black fabric and stitched down the selvages to the black background. The sewn line was 1/8" or so from the edge of the selvage.
The next piece was placed over the raw edge of the first one and sewed down in the same process. I added antique green bias strips to give it some cohesion, although they are tiny pieces of green that nobody else may even notice.
I especially liked the selvage edges that had colored dots on them, but occasionally, I picked a piece that had words on it. Here is what the top looked like after it was complete.
It's 45" W x 60" H. I hope you like it!