Fabric

• Fabric can lend a removable whimsical Halloween design to your mailbox. Cover the mailbox with a piece of batting and staple it to the bottom of the mailbox. Printed Halloween fabric from the local craft store, such as one featuring pumpkins, ghosts or mummies, can cover the batting. For mailboxes with movable flags, place the batting and material underneath them. Variations on the fabric include cutting out the letters for "Trick or Treat" and "Happy Halloween" out of the fabric and using double-sided sticky tape to attach them to the mailbox, one on each side.
  
  

Paint

• A coat of black spray paint becomes the base for a Halloween mailbox decoration. Tap stencils of Halloween creatures, such as skeletons, skulls, ghouls and ghosts, to the sides of the mailbox. Outline the shapes before filling them in with opaque white paint. Mix and match the stencils to create an eerie graveyard scene, by adding headstones with "R.I.P." or dates with names, and include body parts, such as hands and feet, rising from the grave or by the headstones.
  
  

3D

• A three-dimensional design requires more time and effort but makes a huge impact. Spray-paint artificial vines black then drape them from the center of the mailbox to hang over the sides and wrap more black vines down the post. Tuck silk, blood-red rose blossoms into the vines. Glue black toy ravens or crows to the top of the mailbox while white netting creates a spider web at the base of the mailbox and the post. Stick spiders into the web with a couple of eyeball erasers.
  
  

Garbage Bag

• A green garbage bag changes the look of any mailbox. Pull the bag over the mailbox and staple it in place. Use pumpkins cut from orange construction paper with a variety of face designs or paper pumpkin decorations from the local craft store to apply to one side of the garbage bag with hot glue. A witch on her broomstick or one of a witch stirring her cauldron can adorn the other side.