To use a pencil sharpener, keep the pencil and the sharpener in a straight line. Do not insert the pencil at an angle or the point will be subjected to unnecessary pressure and may break.

Pencil sharpeners work very well when new and sharp, but do not last nearly as long as people think. There are a couple of easy ways to check whether a sharpener is blunt:

• Examine the wood around the pointed pencil. If the surface of the wood is smooth, then the sharpener is sharp. However, if the wood is rough or 'furry' then the sharpener is becoming blunt. A very blunt sharpener will produce a very rough surface on the pencil point.
  
  
• Watch the shavings coming out of the sharpener. A good pencil sharpener will produce a long, continuous sliver of shavings. The blunter the sharpener the smaller the pieces of shaving become. If you start to see shard-like pieces coming out of the sharpener, then throw it away.

Again, these do become blunt and will need the blades changed regularly. Many people experience problems with pencil points breaking when using a knife. The trick is to hold the knife at a shallow angle (almost parallel to the pencil) and take off small amounts of wood from each side of the pencil. If the angle is steep the tendency will be to take off too much wood in one go and possibly to cut the strip at the same time.

Once the strip is exposed, then very gentle scraping movements will make a nice sharp point.

All of the above applies to pastel pencils. However, pastels are more delicate than normal pencils. The properties of pastel pencils are specifically designed to be ‘crumbly’ and dusty on paper. This means that they must be handled with more care during sharpening. There is even more risk of snapping the point by being too vigorous with a knife (the sharpening angle for a pastel has to be even shallower because there is less wood around the strip).

Also, the materials that make the pastel pencils dusty are much more abrasive than the materials in other types of pencil. Therefore, blades will blunt quicker than they would normally. New Derwent pastel sharpeners and sharp craft knives will work well for a time, but will need to be replaced regularly to make sure that sharpening can be done properly.