You need a strong stomach, but mint sprigs are provided to help with the noxious smell. Interesting place, but not for the faint-hearted. Tannery tour guide expected a tip even though he clearly was there to lead us to a leather goods shop. Given we spent £60 in the shop I wasn't inclined to give him anything. He started getting aggressive as we left the shop - threatening to go back into the shop and complain to the shop manager eventually made him go away.