Copper vessels are widely used in Hindu pujas and rituals. The reason why copper vessels are used is that it is made from a single pure metal – copper. The vessels are not an alloy or made using a combination of several metals. Drinking water from copper vessel is considered healthy and is believed to improve immunity and blood circulation.
The ancient belief is that vessels made from a combination of several metals are impure. They transfer these impurities into water and puja materials.
Other metals that are used for making puja vessels are gold and silver. As these are costly, vessels made of these are very rare. Silver vessels are used in rich homes and in temples.
Metals that are avoided for making puja vessels are steel, aluminium and iron.
An exception to the above rule is use of Bronze in puja items in South and Eastern parts of India. Puja vessels and lamps are widely made using bronze in Kerala and Tamil Nadu. The material used to make these puja vessels are known as bell metal or gun metal.