Sentence:  I explain that socks can't be boiled up in the <WSD>copper</WSD> with the sheets and towels or they shrink. 
Meaning of the word marked with <WSD> tags:  A large pot, often used for heating water or washing clothes over a fire. In Australasia at least, it could also be a fixed installation made of copper, with a fire underneath and its own chimney. Generally made redundant by the advent of the washing machine.