Shoe companies are wising up to the fact that shoe manufacturing is decidely un-green. Some of them are making athletic shoes made from recycled materials or lighter-weight materials that reduce waste.

New Balance has made a shoe called newSKY made almost entirely out of fabric from post-consumer plastic bottles. Other than foam, small rubber components on the outsole and some water-based glue, the only material is the recycled fabric.

Usually materials like plastic and leather provide shape and structure for shoes, according to New Balance’s web site, but in the case of newSKY shoes, the heel was reinforced with strategic stitching along the back seam and a thicker weight of fabric. “When we doubled-up the material you don’t need any reinforcement because the material is doing it itself,” one designer said on the web site.

Nike is also trying to make its running shoes more sustainable, with a new manufacturing process that weaves synthetic yarn together with a knitting machine. The line of shoes, called Flyknit, consists of fewer pieces than other shoes. The amount of material wasted making each pair weighs only as much as a sheet of paper, producing 66 percent less waste than its Air Pegasus+ 28 brand, the company says.

For people who don’t want to buy new shoes, another way to be green is to repair what you already have. You can take your worn out shoes to the local cobbler or, if you own a pair of Cole-Haan shoes, that company will repair them for you. The company has a restoration program in which people can send in their worn pairs (for a fee) and have the soles, heels, tassles, stitching and hardware replaced. Allen Edmonds offers a similar “recrafting” service for worn dress shoes, ranging from simple heel replacement to complete restoration.