Not all that remains is bone. There may be melted metal lumps from missed jewellery; casket furniture; dental fillings; and surgical implants, such as hip replacements. Breast implants do not have to be removed before cremation. Some medical devices such as pacemakers may need to be removed before cremation to avoid the risk of explosion. Large items such as titanium hip replacements (which tarnish but do not melt) or casket hinges are usually removed before processing, as they may damage the processor. (If they are missed at first, they must ultimately be removed before processing is complete, as items such as titanium joint replacements are far too durable to be ground.) Implants may be returned to the family, but are more commonly sold as ferrous/non-ferrous scrap metal. After the remains are processed, smaller bits of metal such as tooth fillings, and rings (commonly known as "gleanings") are sieved out and may be later interred in common, consecrated ground in a remote area of the cemetery. They may also be sold as precious metal scrap.