There are several types of stone carved into sculptures, so you should know the composition of your statue before you begin polishing it. Make sure that the sculpture is completely dry before attempting to polish. It is safe to polish harder stones, such as granite or marble, to a high gloss either by hand or using a machine. However, while softer stones such as soapstone or limestone can be polished, you'll need to do it lightly and by hand, as the sculpture may chip or otherwise be damaged if handled too roughly.
Wooden sculptures are more common and often less expensive than stone sculptures, as wood is easier to work with than the harder material. Polish will often restore the surface of the wood by hiding blemishes created while sculpting the piece. Only polish wooden sculptures that will be kept indoors and unexposed to weather or water. You can polish wooden sculptures using several different methods. Brush polishing uses a brush to spread the polish over the surface of the wood, whereas rubber polishing uses a piece of cotton wool covered with a white linen cloth to apply the polish. Finish off the piece by adding wax polish and buffing it off for a glossy finish.
Metal sculptures are slightly more tricky to polish, as several metals will be ruined during the polishing process. The patina on a bronze sculpture, for example, will be destroyed if you apply polish to its surface. However, it is safe to polish stainless steel or titanium sculptures. Stainless steel is electro-polished to obtain a glossy, mirror-like surface that will also resist rusting. Titanium, a more expensive material, can also be polished using a dremel tool and rubber wheels specially designed for use on titanium that, with increasing wheel grits, will polish the metal to obtain a reflective shine.
Any sculpture that is left indoors all the time does not necessarily need to be polished, as a soft rag will work to clean it. If you desire a glossier finish, consult the artist to find out the composition of the sculpture and whether it is safe to polish it. When in doubt, always remember that is best to handle most sculptures as little as possible, to prevent damage. Also, remember that bronze sculptures will need to be waxed, but not polished, at least once a year to retain their patina. Know how to handle your sculpture in order to preserve its beauty over time.