good night

I met a shaman from somewhere in South America.  He, through an interpreter, explained the role of water in, and ability of water to, trap bad mojo/evil.  
This has given me pause for reflection many times since I heard this.  I think it is unlikely that water is any better at trapping evil than is the air, the earth, or grandpa.  
While grandpa was living with us, the only respite we ever got, from the evil trapped in grandpa, was accomplished by draping a large opaque blanket over his cage.