Tedious as it sounds, try to collect eight, small, identical bottles and place them on a tray near your front door in order to protect your home. The bottles should contain:

Earth:

-- garden soil
-- sand

Air:

-- nothing
-- incense dust (may be obtained for free from Chinese temples)

Fire:

-- ashes
-- coal dust

Water:

-- alkaline water or mineral water
-- rain water, sea water, or well water