^ I love the 3 box idea for decluttering a room! I am going to use this idea myself!!
As for OP, I haven't been sewing much recently, but do have quite a few fabrics and sewing notions. I purged out my least favorite favorite fabrics, and put everything else back into a big plastic storage tub. It is very helpful to have things contained in the one tub. I think it would work great for art supplies, too.