How often should you cleanse? Even if you don't wear make-up, your face will be dirty by the end of the day as dust in the air clings to the natural oil coating your skin. And if you do wear make-up, the base for surface grime is that much stickier. It makes sense then to clean your skin very thoroughly at night, and again lightly in the morning, to remove the night's output of sweat and sebum.

There's really no need to clean your face more often than this - removing sebum throughout the day could well cause over-dryness. Only if your face is really greasy should you include a lunchtime clean sweep. But if you are putting on makeup for the first time late in the day, a light cleansing will ensure cosmetics go on to your skin smoothly.

Soap or cream? The simple facts are that soap is a good remover of dirt and natural oil, but is not effective as a make-up remover. Cream cleansers are specially designed to dissolve the waxes and pigments used in cosmetics. Soaps have a more drying effect than creams, while creams can leave a greasy film on the skin. The answer? Cream cleanser followed by soap and water for normal-to-oily skins, cream only for dry ones.

What's in your soap? Soaps come in many forms - liquid, solid, perfumed, superfatted, medicated and mild. But any soap that is designed to do more than simply clean your skin can only do it harm. Perfumes irritate, medication over-dry, and moisturising should be a separate process, so superfatted soaps are pointless. The simplest solution is to use the plainest unperfumed soap you can find.

What are soaps made from? Basically fat and lye (an alkaline substance of wood ashes and water. The alkalinity of soap can upset the skin's normal acid/alkaline (pH) balance, but skin is cleverly designed to restore itself to its naturally slightly acid state within 20 minutes after washing. You could help the process along by adding a little lemon juice to your final rinse.

The fats in soap combine with hard water minerals to form an insoluble scum in your rinsing water. You can combat this by adding a pinch of borax to your final rinse, or by using a detergent-based liquid soap, as these are made from petroleum derivatives and don't make scum.

Soapless complexion bars are a water-soluble version of cleansing creams. They don't lather much but are a good choice for the dry-skinned who want a very mild cleanse water. Newer arrivals are foam cleansers and creams which can be rinsed off.

The right way to wash Make sure the water is warm, not hot. With clean hands, work up a soapy lather and massage over the face in light circular movements. For areas with blocked pores use a face brush, sponge or  rough flannel to lift surface cells. Rinse thoroughly with running water.