This covers solid/inert materials, which are sometimes described as rubble. They must be unreactive, and solid, so amounts of clay, soils and lime stone would not be included. They could include cinder blocks, bricks (or anything else used to make a wall!), render, sand, set cement, ceramic tiles, solid stone tiles, reform stones.
Glass can be included in this category, but it is best to check with the business removing the waste type, as sometimes glass is collected separately. Also the companies offering the best price on these usually only want solid, uncontaminated, hardcore, as this can easily be processed into new aggregates. The best prices can usually be obtained from companies that handle aggregates for sale. Other companies are less “fussy” and will accept quite a mix, but charge a little more.