Sterilise

"The use of heat as a sterilising agent is a method of long standing and is particularly effective against most insects. Insects are very susceptible to high temperatures, the ultramaximum temperature—the temperature which will kill an insect instantly—being for the great majority of insects about 140 degrees F. A moderately high temperature, however, if applied for several hours is usually as fatal as a much higher temperature applied for a shorter time."