In order to avoid cross scratches, work should be "sanded" with the grain, even if this takes much trouble.

For flat surfaces, and to touch off edges, it is best to wrap the sandpaper over a rectangular block of wood, of which the corners are slightly rounded, or it may be fitted over special shapes of wood for specially shaped surfaces.

The objection to using the thumb or fingers instead of a block, is that the soft portions of the wood are cut down faster than the hard portions, whereas the use of a block tends to keep the surface even.
[Illustration: Fig.156.Sharpening a Cabinet-Scraper: 4th Step, Turning the Edge.] _Steel wool_ is made by turning off fine shavings from the edges of a number of thin discs of steel, held together in a lathe.

There are various grades of coarseness, from No.

00 to No.3.Its uses are manifold: as a substitute for sandpaper, especially on curved surfaces, to clean up paint, and to rub down shellac to an "egg-shell" finish.