I wet down my recently nålbound hat with soap and water to do light fulling (locking wool fibers together in fabric) and was quite surprised when the stitches relaxed and the hat lengthened.

I intentionally made the hat larger because I know that wool hats shrink with wearing because of the natural fulling process from moisture and movement. I agitated the hat in the gentle soap and water to deliberately start the felting process, not expecting that much change with the Oslo stitch I used. I wanted the hat to be a slouch hat with folded brim, so really it came out remarkably well, serendipitously.