If you're throwing away glue containers, tubes or bottles, make sure there's no wet adhesive inside -- it can contaminate the garbage and create a chemical cocktail in the landfill. The key thing is to let the glue dry out completely. The simplest way to do that is to open the container and let it air dry. A faster way is to spread the glue on old newspapers, or use a knife to cut a slit down the tube to let it air dry. When the glue or adhesive is hard, you can safely throw away the whole thing without fear of contamination.