“Recyclables” by Streetwise Cycle – Own work. Licensed under Public Domain via Wikimedia Commons – https://commons.wikimedia.org/wiki/File:Recyclables.JPG#/media/File:Recyclables.JPG
A single half-empty soda bottle can contaminate an entire load of recyclable plastic at the processing plant, sending thousands of pounds to the landfill instead of being recycled.
While a little bit of leftover food can seem harmless, mold and bacteria can feed on the debris, multiplying as the recyclables sit in the hot sun on the way from your curb to the recycling center.
Recycling companies do wash the items, but many sort the incoming material according to its cleanliness. So the dirtier the plastic is, the less valuable it is to recycle since it takes more energy (a thorough cleaning can be expensive) to convert it into a usable material.
Rebecca Harrington 
