Remove the mattress and box springs, if applicable. Place a blanket next to the bed frame to hold the disassembled pieces if the floor is a hardwood floor. This prevents damage to the wood.
Put on a pair of work gloves. Choose which end, the head or foot, you wish to begin with -- it does not matter which end. Loosen the wood posters by gripping them firmly and turning them to the left with one hand while your other hand grips the headboard or footboard. You should feel movement.
Loosen the wood poster on the other side of the footboard or headboard. Tug at the board while pushing in the opposite direction on the poster. If it does not separate, use a rubber mallet to gently tap at the poster. Repeat on the other side to remove the posters from the board.
Check for extra hardware securing the side slats to the posters. You may need a screwdriver or an adjustable wrench to remove some hardware. If none exists, use your rubber mallet to gently tap at the interior of the bed legs to separate them from the side slats. When you've completely removed this section, lay the parts aside on the blanket.
Move to the other end of the bed frame. Repeat the same procedure on this side as you did before to remove the posters and the side slats from the board.