a method for recycling plastic and manufacturing filler involves collecting discarded plastic articles , and grinding / shredding the articles up together without substantive sorting out of the articles by plastic type , color , etc . the plastic articles are shredded into shredded plastic particles which are used as filler for various consumer products , such as weight training equipment and cushions . for products requiring additional weight , higher - density shredded recycled plastic particles are added to the filler for increased weight . for products requiring less weight and / or buoyancy , lower - density recycled plastic particles and / or foam is added to the filler for decreased weight / density . weight training bags , pet training devices , cushions pillows , flotation devices , ski racks , and other products may be formed using the filler .