Sharpening a knife is best about a special stone. Its abrasive surface is just perfect for this. Even the newfangled metal sharpeners are inferior to him - they erase the blade too quickly. But if there were no special devices, for example, in a campaign or other "extreme" conditions, you will have to use improvised means.
Tableware
A good substitute for grindstone is glass or porcelain. The bottom of the mug or saucer usually has a rough surface having excellent abrasive properties. Turn the mug over and place it on a table or ground. Several times draw a knife along the unfinished circumference of the bottom with sliding movements, slightly at an angle. The result will be quite acceptable, even the most dull knives acquire good cutting properties.
Unlined Glass Edge
Such an edge can be found, for example, on the side window of a car, if you lower it. Being in places where a person is staying, getting a piece of glass will be a fairly simple task. The sharpening technology is the same as when using china. If you do not use car glass, but a splinter, be careful. To avoid injury, wrap a sharp surface with a piece of cloth or clothing.
Metal
You can use a second knife in order to sharpen a blunt. Move with the sharpening movements of one knife against the butt of another. Of course, some skill is needed here, since in the absence of experience the result leaves much to be desired. Replace the knife can metal grill gas stove.
In addition, other metal objects can be used as a sharpener: a piece of steel wire (it should be fixed on both sides) or, for example, a belt buckle, only choose the roughest edge.
Stones, bricks, concrete facade
Pebble has excellent grinding properties, if you are outdoors, near water, look for a medium-sized pebble, not too smooth. Smooth, without chips, silicate brick is almost a full-fledged substitute for a grindstone, red clay is most likely not suitable, it is too soft for such purposes.
Concrete facade, step, slab - all these objects can help you to give the knife the best cutting properties, however, choose a smooth concrete surface if possible. In extreme cases, a piece of sandpaper will do.
