Witch Shrines

Witch Shrines are occult shrines that allow for otherworldly entities to gain access to our realm. They can be made pretty much anywhere, and consist of things like candles, effigies, bones, magick items and spell books, etc. They are traditionally kept at home or in places sacred (and preferably secure) to the Witch in question.
Destroying a Witch Shrine is easy, just take it apart. But doing so may cause something from the netherworld to take notice that a gateway into the material world is closing, and it may jump through at the last minute...
Also, Witch Shrines allow Witches (and most other Mages) to work their Magicks with greater ease and less cost to themselves.