The box containing the body is placed in the retort and incinerated at a temperature of 760 to 1150 °C (1400 to 2100 °F). During the cremation process, the greater portion of the body (especially the organs and other soft tissues) is vaporized and oxidized by the intense heat; gases released are discharged through the exhaust system. The process usually takes 90 minutes to two hours, with larger bodies taking longer time.[citation needed]
Jewellery, such as necklaces, wrist-watches and rings, are ordinarily removed before cremation, and returned to the family. Several implanted devices are required to be removed. A pacemaker could explode and damage the cremator and potentially staff nearby; spinal cord stimulators have similar power sources, and implanted drug reservoirs may produce lesser bangs. A specific variety of bone nail use in the femur and humerus is a hollow shell which is inflated with saline under high pressure to grip the interior of the bone, and constitutes a bomb in the cremator. In the United Kingdom, and possibly other countries, the undertaker is required to remove such devices prior to delivering the body to the crematorium, and sign a declaration stating that no hazardous device remains in place.[11]
Contrary to popular belief, the cremated remains are not ashes in the usual sense. After the incineration is completed, the dry bone fragments are swept out of the retort and pulverised by a machine called a Cremulator essentially a high-capacity, high-speed blender to process them into "ashes" or "cremated remains",[11][12] although pulverisation may also be performed by hand. This leaves the bone with a fine sand like texture and color, able to be scattered without need for mixing with any foreign matter,[13] though the size of the grain varies depending on the Cremulator used. Their weight is approximately 4 pounds (1.8 kg) for adult human females and 6 pounds (2.7 kg) for adult human males. There are various types of Cremulators, including rotating devices, grinders, and older models using heavy metal balls.[14]