To dismantle furniture, it is important to remove the glue, and then twist the wood gently to loosen the joint. If the furniture has a peg holding it together, remove the peg, too.
To start removing the glue, drill small holes using a 1/8-inch drill bit into the joint. For spindles or chair legs, use three to four holes about 3/4 inch deep. For square or flat joints, drill the holes into each edge with glue. Depending on the type of glue holding the wood together, use products such as acetone or warm water to remove it. Put the product or glue solvent into the holes, and allow it to work for about 10 to 20 minutes.
When the solvent has had a chance to work, begin gently twisting the wood to loosen up the joint, and then pull it apart. If the joint does not move, allow the solvent to sit for an additional 10 to 20 minutes. If pegs hold the leg in place, use a small hammer to remove it.
If the solvent does not work to loosen the joint, use a heat gun and point it directly at the joint. As the joint heats up, begin rocking the joint. When the joint begins to move, remove the heat and pull it apart. Sand the edges after removing the legs, and then smooth out the gouges.