Yantras do not need to be bathed daily, they can be cleaned on special occasions, you can apply tilak of Kumkum (Goddess Yantra) or Saffron Chandan (Dev Yantra) to them daily. Worship of silver yantras is auspicious for 25 years, whereas worship of metal yantras like copper, brass is beneficial only for one and a half years. Yantras built on gold or gem stones are worthy of worship for life. On the basis of the percentage of gold and silver in the yantras made of mixed metal, their age will be calculated! Yantras written on Bhojpatra are also very effective! It is to be noted here that every yantra should be energized according to the prescribed procedure, only then there is the benefit of its installation, otherwise they are enhancing the beauty according to your faith!
The yantras have always been made by their shape types, numbers, and letters. Simple and more useful yantras will be made of squares and numbers, which people keep reading names without understanding, but influential or secret ancient yantras consist of shapes, numbers and seed syllables or letters known as beej aksharas, which only seekers can understand, this is a science.