Hamburg  - The wrong summer shoe can quickly ruin an entire vacation day.

To make sure thong-style sandals don't pinch or rub, women should be very selective when buying a pair.

"You can't do much about it after you've worn them," said Konrad Weissler of Germany's shoe institute in Offenbach. The shoe must fit the foot. There's no shoe care for the parts of the shoe that

rub or the part that fits between the toes.

"If a there's a hint of rubbing when trying on the shoe, it's best to leave it. Or if the shoe is not that nice," said Weissler. Not every shoe fits every foot because feet vary according to the shape of the toes and the ball of the foot and the sensitivity of the skin.

"That's why the ridges of the shoes have to fit. If they are only a milimetre too tight, they rub and you can't do anything about it," she said.

Smooth leather is generally better than raw material. Above all, material with smooth edges make it easy on the feet. Braided or bound leather, on the other hand, can be soft, but again, the shoe must fit well. Some are only finished on the outside with velvet, while inside they are plain leather.

"Such details reveal the amount of work that has gone into the shoe," said Weissler. (dpa)