Originating in the 19th century, when small ornamental figurines grew popular, chalkware was all the rage for decorative purposes. Today, we'd call them knick-knacks. Back then they were made of fast-drying Plaster of Paris, a simple ceramic that didn't need to be kiln fired to dry hard. Its popularity means that chalkware is relatively easy to find. Unfortunately, most pieces are damaged due to the soft nature of the plaster used and the relative carelessness with which the pieces were handled in the past.
Wipe dirt and debris from the surface with a soft cloth or soft bristled brush. Don't wet the cloth or brush, as chalkware dissolves in water. You probably won't be able to remove all stains and dirt from the piece, but this is OK for most collectors.
Clean small nooks and crannies with a Q-tip or small pointed brush. This is also good for wiping off ground-in dirt and debris from the surface of the statue.
Gather all pieces of the statue together. Examine them to determine how they fit back together and to see if any pieces are missing. You can fill in missing spots with a homemade paste.
Take a small piece of chalkware, if painted, to the local paint store for a paint-matching service. You are looking for a water-based acrylic with a matt finish. You will also need to buy white gesso for a base coat.
Match the broken pieces together to determine the proper fit.
Apply a small line of Elmer's glue to the broken sections.
Press the pieces together and hold in place until glue sets. Wipe off excess glue that gets squeezed out. Let dry for 24 hours.
Make a paste of Elmer's glue and baking soda or Elmer's glue and chalk powder. Start with a 1:1 ratio and add more powder until you get a slightly doughy consistency.
Pour or press into the missing areas and sculpt to match the surface. You can use a toothpick, brush or artist's trowel to sculpt.
Allow to dry for one week.
Clean the surface to be painted and check that it's smooth or shaped appropriately to suit the rest of the sculpture.
Lightly sand the surface to remove any unwanted imperfections. Chalkware is very soft, so don't press down too hard.
Apply a thin layer of white gesso to seal the surface of the chalkware. Don't dilute the gesso with water. It is supposed to be thick, but a little bit goes a long way. Allow the gesso to dry for a couple of hours.
Paint over the gesso with a water-based acrylic paint using a soft bristled brush. Match the paint to the original paint colour. Allow the paint to dry for a couple of hours.