It includes any waste material. I hope this helps and is clear.

scrap doesn't necessarily specifically refer to "recyclables" unless you are saying "I want to recycle this scrap" or unless the context of the discussion is referring to recycling. Scrap can refer any kind of material - it depends on the context of where you are or what you are pointing to. If you are in a printing factory, the scrap is wasted paper, books or printed material. In a plastics factory, it would be wasted plastic. Scrap only becomes a "recyclable" if it's actually recycled - otherwise, it's simply sold or thrown away as "scrap". When it's sold, the person buying will either use it to burn (to keep warm) or recycle it to make a new product. However, the most common use of "scrap" today is when it's short version of "scrap metal". Scrap metal is big business these days and generally when people are talking about scrap, they are normally referring to scrap metal.

Yes, scrap can refer to metals, paper, wood and other materials. But not with actual products, like cans or bottles. It refers to excess material. When you cut a piece of metal, you end up with pieces that can't be used. They are scrap. Same with paper. Say you cut a shape out of a piece of paper. The extra pieces are scrap paper. And when you build something with wood, you end up with a lot of scrap wood laying around.

I've only ever heard it used to describe metal.