The law of mbira used to be very demanding. It was an instrument that was played only inside the house; it was not an instrument that was taken outside. It was played inside the house of the great spirit mediums, the banya. You were not permitted to take either the mbira or mateze resonators back to your home. Once you had finished playing, you would leave them there, right inside the banya. You would leave them there, and exit empty-handed.
The law of mbira says neither the soundboard nor the deze resonator should be touched by a person who has recently given birth. When a woman gives birth, she must wait for three months before touching her mbira. In the third month, that is when she may start to play mbira. During her time of the month, a person should wait a week before touching the mbira. Then, there is the case of what happens if you physically injure someone. If his blood has spilled upon you, you are marked by blood when you take leave of him. It is akin to killing someone. You must not touch the mbira, because mbira do not favor bad things. They require only good things. They demand people who are pure. That is why they stayed in the banya, without being taken outside.
Another reason we were prohibited from keeping mbira with us at home is that perhaps someone might come by – let’s say my friend stops by after being with girls. Or he has slept with his girlfriend, and he comes and touches my mbira. If he picks up my mbira and plays it, it will break. When I come back, the first thing I do is to pick up my mbira – “Who has broken my mbira?”