Scraperboard is an unusual "drawing" medium, very different of course from painting.  Some people know this as "Claybord"
(a product name) or maybe more know it from yesteryear as "scratchboard", which was an entirely different product twenty, thirty years ago. Today it is much easier to work with. In essence Scraperboard is a smooth masonite board on which a layer of white clay followed by a layer of
black ink is applied on top.  Scraperboard accepts a variety of tools for scraping away the black to reveal the white clay beneath.
I buy it prepared and "ready to go" in assorted sizes. Tools range from a variety of small, sharp, chisel-like instruments to sandpaper to steel wool or anything that will scratch the surface. It can be a bit laborious to scrape large sections of black away, especially if large areas of white are incorporated, and much black dust is left behind, but it is also rewarding to develop an image basically in reverse, that is by drawing or scraping the highlights or lightest values and leaving the darkest alone. Some people equate this medium with etching, but no acid is used, just the tools with which one scrapes. Mistakes have to be carefully avoided!