Yarn is the traditional medium of knit and crochet. However, using non-traditional "fibers" produces some very great and green results.
Knit and crochet using something completely different from yarn can inspire, impress, and certainly recycle.
Jersey Loops
Jersey loop looms are popular gifts for young children, as they introduce kids to the fiber arts in a friendly way. There is a way to use up any of those cotton loops that may be left over after the child is ready to move on to using yarn.
First, the loops must be connected to each other to form a ball of material (very much like a ball of yarn.) Lay two overlapping loops down. Fold one loop over the other, and pull it under itself as shown in Figure 1. Pull both loops until they are securely fastened together (Figure 2).
Do the same thing to connect a third loop. Continue until all the loops are connected, and a long “rope” is made. Wind it into a ball; it should resemble Figure 3. Now, use a large hook (a size “S” works well) or large needles (size 17's are good) and knit or crochet as usual. Jersey loops crocheted or knitted in this manner make great sturdy items, like potholders or rugs.
Using loops can become addicting, as the items made from them have patterns that are hard to duplicate. Make loops instead of buying them by cutting up old socks, old shirt sleeves, and anything else that can be cut into loop shape.
Try crocheting with twine, rafia or a thin rope. The result will be very jute-like. A doormat is the perfect project for using thin rope in this manner, as the texture will be a bit rough—great for wiping mud off shoes. Once comfortable with this concept, another great item to create is a sun hat. It will look very much like straw was used.
Material strips have become so popular in knit and crochet that they come pre-cut. However, originals can be made using bed sheets, old clothes, curtains, and anything else pliable enough to be knit or crocheted.
Plastic bag crochet has been popular with the green crowd for a while. Beautiful carrying bags can be knit or crocheted out of clean garbage bags or grocery bags. If this sounds implausible, take a look at Figure 2.
Old speaker wire is just one more medium to try. Incredibly original artwork has been made out of this unlikely "fiber"-- one example is shown in Figure 3. Other durable projects, such as doormats and tool belts, turn out well.
Leather strips are easily manipulated with regular crochet hooks and knitting needles. These come precut, but can be self-made out of old leather jackets or pants. Belts and bracelets are easy first projects.
Crocheting or knitting regular wire has been very popular as of late. Crafters combine crochet, wire, and beads to make stunning jewelry. A wide assortment of books are available on the subject.
Try coming up with other ideas. Don’t discount anything, even if it sounds a bit odd at first. If it’s pliable, it’s knittable or crochetable.
More non-traditional material ideas can be found in Re-Using Yarn, Wire Crochet, and The Spaghetti Rug.