Clothing for men and women was made from wool, silk, and linen and was usually brown in color. Men also wore leather clothing, such as neckpieces, breeches, ankle leathers, shoes, and boots; and metal belts under which they carried knives or axes. They could wear leather pouches for carrying items. Water could be carried in leather bags. Leather working preservative techniques improved so that tanning prevented stretching or decaying. For their meals, people had drinking cups and bottles made of leather, and bowls, pans, and pitchers made by the potter's wheel. Water could be boiled in pots made of iron, brass, lead, or clay. Some lords had markets on their land, for which they charged a toll [like a sales tax] for participation. There were about fifty markets in the nation. Cattle and slaves were the usual medium of exchange. Shaking hands was symbolic of an agreement for a sale, which was carried out in front of witnesses at the market. People traveled to markets on roads and bridges kept in repair by certain men who did this work as their service to the King. Salt was used throughout the nation to preserve meat over the winter. Inland saltworks had an elaborate and specialized organization. They formed little manufacturing enclaves in the midst of agricultural land, and they were considered to be neither manor nor appurtenant to manors. They belonged jointly to the King and the local earl, who shared, at a proportion of two to one, the proceeds of the tolls upon the sale of salt and methods of carriage on the ancient salt ways according to cartload, horse load, or man load. Horses now had horseshoes. The sales of salt were mostly retail, but some bought to resell. Peddlers carried salt to sell from village to village. At seaports on the coast, goods were loaded onto vessels owned by English merchants to be transported to other English seaports. London was a market town on the north side of the Thames River and the primary port and trading center for foreign merchants. Wheat, meal, skins, hides, wool, beer, lead, cheese, salt, and honey were exported. Wine (mostly for the church), fish, timber, pitch, pepper, spices, copper, gems, gold, silk, dyes, oil, brass, sulphur, glass, and elephant and walrus ivory were imported. There was a royal levy on exports by foreigners merchants. The other side of the river was called Southwark. It contained sleazy docks, prisons, gaming houses, brothels, and inns.