Chicken and cow manure, old newspapers, straw and wood chips can be used to clean up land contaminated pesticides such as DDT, according to Canadian scientists at the Life Sciences firm Astra Zeneca. Finding a practical way to clean up contaminated land is tricky. Digging up soil and moving it elsewhere is no longer acceptable, sealing it in a landfill site is now illegal in the United States, and heating it in massive kilns to burn off offending pesticides is expensive.