I have a black acrylic knit cardigan that I absolutely love. Unfortunately, because it was kind of cheap it pills very easily, and began to look a bit worn out. I tried using a lint roller on it, but because the pills were attached rather than loose fluff or lint on the surface, it didn't really work. I remembered that my mom used to have a small electric tool which would buzz over the surface of the fabric and remove pills, and after a little experimenting, I discovered that if you get a disposable razor and lightly shave the surface of the fabric, it'll remove the pilling. You can then use a sticky lint roller or just some sellotape to remove the shaved-off fluff. My sweater looks like new again! It takes some time, but it's much more worth it than spending money on a new cardigan (especially since I wear this at work a lot).