Mixed paper includes phone books, white paperboard (white dry food/material boxes), brown paperboard (cereal boxes, paper towel rolls), white and colored non-standard office paper (construction paper, card stock, tablet paper), soft cover books, and folders. 

Mixed paper cannot include adhesives (envelopes), wax-coated paper, plastic-coated paper, or plastics or metals (spiral binders, plastic folder covers, paper with plastic windows).

In other words, mixed paper includes:

• Paper of all kinds - not just newspapers and office paper! We mean junk mail, construction paper, old birthday cards, cardstock, and any other non-standard paper. Staples are fine.
• Paperboard (Packaging, cereal boxes, paper towel rolls, etc which are clean and dry)
• Soft books of all kinds (Phone books, paperback novels and magazines are examples.)