At one time there were 6000 local tanneries and Claytons is one of only 3 that are still in operation today. It was originally at Spa Lane until they moved to their present site in 1870, and today's premises have changed little since then with many of the original pits and machinery still in use. The tanning process goes back many thousands of years, and was at one time regulated by guilds set up in 1444 which imposed conditions such as the tanning process was to last for a year and a day. The skins are scrapped (one at a time by hand) and dipped in pits containing caustic chemicals, then set in drums to remove the hair. The more pits containing acids and enzymes breaks down the proteins in the skin. In the vegetable tanning yard the skins are moved through the pits containing liquids of increasing strength, a process taking 6-8 weeks, then are set in drums (which were steam powered until 1950's) which flex and tan them. The tannin is then washed off in the 'currying' area, and oil and grease used to make them flexible. Finally the leather is selected and graded, dried hung on or stapled to special frames and finished on one of the many printing, colouring and embossing machines.