Altar Protection

Start off by putting some Holy/Blessed water onto the rag.  Wipe down the surface of your altar and anything that collects dust.  Then, get some white sage, or dragon's blood, and smudge the area, fanning the smoke around.  You may make a pentacle symbol with the smoke around your altar.  As you smudge, you may say a blessing, prayer, etc.  Imagine the the negativity moving out of the area, and visualize protective energies moving in.

After you are done smudging, charge a Hematite crystal with protective energy.  You can do this by holding the crystal in your hands, and focus on the protective energies.  Visualize your altar being protected.  Then, place the Hematite somewhere on your altar.