Abstract: Process for packaging sticky substances in the molten state, in which the sticky substance is cast in a tray-mold lined be-forehand with a film of non-sticky plastic material and compatible in the fluid state with the sticky substance, including, among other, the phase of lining the internal walls of the tray-molds with a first thin and easily formable film of the non-sticky plastic material, causing it to perfectly adhere to the walls of the mold by connecting the lower external part of the molds connection to a vacuum source, in which the degree of vacuum during the opening transient of the connection is modulated.