[This information comes from the LAPADA website with their permission. You may read the entire unedited information on their website by clicking here.]
'Ceramic', from the Greek keramos meaning clay, is the generic term for all items made from clay and fired in a kiln. Depending on the type of clay, which other elements have been mixed with it and the temperature at which it was fired, the end result may be referred to as porcelain, pottery or stoneware.There are then further terms used to distinguish different types including hard paste and soft paste porcelain, bone china, biscuit, earthenware and creamware. The word 'china' is not therefore used in the field of antiques except for bone china which is a hard paste porcelain mixed with animal bone ash to make it whiter.
Although ceramics, and also glass, can be affected by strong light and by extreme fluctuations of temperature and humidity, the risk of breaking or cracking them is the greatest danger in the home. Strong sunlight can, in time, cause an area of some types of ceramic to fade and adhesives used in restoration can be discoloured or weakened by strong light or water. Unglazed pottery, being porous, will absorb water and any impurities it contains may result in staining. On unglazed pieces, greasy fingerprints can leave indelible marks.
Handling, Display and Use
Always pick up an item by the body, avoiding an extremity such as a handle, spout or head. Support the base and be careful of loose parts such as lids. Valuable and delicate pieces are best displayed in a cabinet in which the shelves should be stable to avoid vibrations. It is helpful to place items on a felt or chamois pad cut to fit the base which will also protect the shelf or piece of furniture beneath.
Remove dirt and dust from any decorative pieces with a dry artist's paintbrush before washing. Provided they are unrestored, glazed ceramics can safely be washed in warm water with a little washing-up liquid, using a soft brush to coax dirt from crevices, but never use abrasive cleaners or put antique pieces in the dishwasher. When washing, protect the pieces by laying a towel or sponge at the bottom of the, preferably plastic, basin, or stand one piece at a time on the draining board and wash gently with a soft brush dipped in water with washing-up liquid. Rinse well and leave to dry on a clean towel. A warm hairdryer can be useful for drying intricate items.