If moldings and trim are badly damaged, it's best to replace them. This work isn't particularly heavy or difficult, but it does take a little experience at making accurate cuts using a miter box. If this isn't something you have done before, you're probably better off calling a finish carpenter or cabinetmaker to do the work. You may be able to save a few dollars by removing the old trim yourself.

Here's how:
1. Use a utility knife to cut through any paint seal between the trim and the wall.

2. Slip a putty knife or scraper in behind the trim and pry it gently away from the wall--don't bend the tool. Next, fit the hooked end of a flat prybar into the separation behind the putty knife and press against a flat wood block that has been placed against the wall (so you don't damage the wall).

3. Door and window trim is often nailed with a small nail at the mitered corners. If you pry at these points, the wood may split. First, use a mini-hacksaw to cut off the nails at the joint. If you do split trim when removing it, just glue it and rubber band or tape it together with masking tape until the wood dries.

4. When you remove the trim, don't knock out the nails from the backside--they'll break away the face of the moldings. Instead, use slip-joint pliers to pull them all the way through from behind.

5. Replace with new trim, using a fine-toothed saw, backsaw, or miter box to make the necessary cuts.