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