Washing your hair too infrequently is more likely a problem than washing too much, as the scalp rarely dries out.

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"One minute I would be standing in the shower washing my hair and the next minute sitting in the tub sobbing uncontrollably, " she wrote in her book.

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Henkel is home to a whole host of different brands from Persil washing-powder to hair products such as Schwarzkopf.

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Who, for example, can name the inventor of the hair-dryer (Chester Beach), the electric washing machine (Alva Fisher) or the ice lolly (Frank Epperson)?

ECONOMIST: Encapsulating a century in gadgets

The AOA recommends washing glasses every morning, paying special attention to the frames and earpieces, where hair product and makeup tend to rub off.

WSJ: How to Clean Your Glasses Properly