In an effort to keep my knitting projects neat, I used to use a plastic Zip-loc bag. If you are like me and are looking for a more eco-friendly solution, you need a Natural Mesh Bag.
It has been designed to open wide to accommodate a large wound skein (or two smaller ones), and then added snaps that allow you to customize the size and configuration. The bags are made out of woven, washable paper fabric which is both sturdy, yet lightweight.