What happens to the materials that aren’t recyclable? Don’t they just get recycled anyway?

As much as we would like to recycle everything we receive, it’s a matter of market demand. We cannot collect and process materials if there is no one to buy them economically.  Similarly, if we include too much “junk” with our materials (such as shredded paper or plastic bags mixed in with the cardboard), we risk losing buyers and/or getting a lower price for our materials which will cost more in the end.  Undesirable materials and contaminants are landfilled.