Tim, would you mind describing how you do this? I'm still not following how a skew can be used like a negative scraper.
A skew is usually used with the handle down and blade upward and cutting in at an angle. When used as a "scraper", it is laying flat on the tool rest, handle presented level to the blank. Since the skew is beveled on both sides, and presenting the blade flat and level to the blank, the blade end is at a negative angle.
Notice that Randy posted a picture and how the end of the blade is ground slightly downward - the end of the skew, when presented this way, the blade edge is also slightly downward. This is a "negative" angle when presented level to the blank.
BTW, this is not what is commonly referred to as the purpose of a skew. While using the skew as scrapper is OK, it is not what wood turners refer to as the intended use of a skew. Skews were originally intended to "cut" . . . not "scrape". But when used flat as a scraper, the bevel of the end comes in contact at a negative angle, ergo "negative scraper."