Grasscycling refers to an aerobic (requires air) method of handling grass clippings by leaving them on the lawn when mowing. The term is a portmanteau combining "grass" and "recycling", and had come into use by at least 1990 as part of the push to reduce the huge quantities of clippings going into landfills, up to half of some cities' summertime waste flow, as 1,000 square feet (93 m2) of lawn can produce 200 to 500 pounds (90 to 225 kg) of clippings a year. Optimal grasscycle techniques include: Although a mulching mower can make grass clippings smaller, one is not necessary for grasscycling.