Gilashin zafin jiki ko taurin gilashi, ana yin shi ta hanyar dumama gilashin da aka rufe a zafin jiki na kusan 650 ° C (1200 ° F) sannan iska ta sanyaya cikin sauri.Wannan tsari yana kulle saman gilashin a cikin matsawa wanda matsawa wanda ke ƙara ƙarfin gilashin.Lokacin da zafin jiki ya cika wannan gilashin yana da ƙarfi kusan sau huɗu fiye da guntun gilashin da aka rufe.
Mafi mahimmanci, lokacin da fushi ya karye yakan rabu cikin ƙananan ƙananan waɗanda ake la'akari da yanayin rashin lafiya.