THE CAULDRON AND THE KNIFE
before going to bed, fill a cauldron (or iron bucket, bowl or pot) with
water and place it inside your house near the front door. Take a very
sharp knife or Athame and place it point-down
into the water, saying:
"Into the water I place this blade,
To guard against the thief and shade.
May no flesh nor astral shell
Enter this place wherein I dwell"
is a good protection spell, and can be performed every evening. In the
morning, remove and dry the knife, and place it somewhere safe. Then,
without touching it, pour the water outside, (or down the drain if
necessary) and put the cauldron away.
It probably wouldn't be a good idea to do this spell if you're expecting company, as it could be dangerous (and wet).
You can do this at each door if desired, and protects against more than corporeal forms.