Slice through the paint line at the top of your baseboards with a utility knife. This prevents the dried paint at the top of your baseboards from pulling paint off your wall when you pry the boards free.
Wedge a chisel tip into the gap between the baseboard and the wall. Tap the chisel gently with a hammer, slightly separating each baseboard from the wall.
Push a wide putty knife down into the open space your chisel created. Wedge the curved tip of a pry bar into the space.
Pull back gently on the pry bar until the baseboard falls away from the wall. Turn the baseboard over. Number the baseboard and the wall with a pencil. This helps you remember exactly where the baseboard goes when you are ready to re-install it.
Pull the nails through the baseboard from the back with a pair of pliers. Discard the nails.
Examine each section of baseboard for minor damage, such as chipping. Fill in any chips or scrapes with wood filler. Let the wood filler dry for the amount of time specified on the can.
Match up each baseboard with its corresponding section of wall using the previously marked numbers.
Nail each baseboard section into place with 1½-inch finishing nails.
Touch up nail heads and any exposed wood filler with paint the same shade as your baseboards.
Caulk the space between the top of the baseboard and the wall with silicone or latex caulking. This not only secures your baseboards; it also hides any exposed cut lines that mark where each baseboard was previously attached to the wall.