These continued in use for "ironing" in some places into the mid-19th century, long after Western blacksmiths started to forge smoothing irons in the late Middle Ages.laundry from 1800 Flattish hand-size stones could be rubbed over woven cloth to smooth it, polish it, or to press in pleated folds.
Water may have been used to dampen linen, but it is unlikely the smoothers were heated.
More recent glass smoothers often had handles, like these from Wales, or the English one in the picture (left).
They were also called slickers, slickstones, sleekstones, or slickenstones.
Decorative 18th and 19th century glass smoothers in "inverted mushroom" shape may turn up at antiques auctions. Slickstones were standard pieces of laundering equipment in the late Middle Ages, in England and elsewhere, and went on being used up to the 19th century, long after the introduction of metal irons.
Simple round linen smoothers made of dark glass have been found in many Viking women's graves, and are believed to have been used with smoothing boards.
Archaeologists know there were plenty of these across medieval Europe, but they aren't completely sure how they were used.
They were convenient for small jobs when you didn't want to heat up irons, lay out ironing blankets on boards, and so on. Medieval launderers preparing big sheets, tablecloths etc.
for a large household may have used frames to stretch damp cloth smooth, or passed it between "calenders" (rollers).
No-one can say exactly when people started trying to press cloth smooth, but we know that the Chinese were using hot metal for ironing before anyone else.