A heating applicator system comprising: a disposable first subassembly that comprises: a reservoir that has a top end in the form of a hollow neck, the neck having an upper orifice that provides access to the interior of the reservoir; a hollow neck extension that is connected to the neck of reservoir in a detachable and reattachable manner, such that the upper orifice of the reservoir is surrounded by the neck extension; and an applicator head that depends from the neck extension and passes through the upper orifice and into the reservoir, the applicator head comprising: a hollow stem that has an opened proximal portion and a closed distal portion, wherein the closed distal portion supports a working surface; such that, when the reservoir, neck extension and applicator head are assembled, the interior of the reservoir is sealed off from the ambient environment, and the working surface of the applicator head is immersed in the reservoir; and a passage exists through the neck extension, and into the closed distal portion of the applicator head; and a reusable second subassembly that comprises: a hollow handle having a proximal end and an opened distal end; a power source located in the handle; a hollow, electric heating circuit housing that has an upper end and a lower end, wherein the upper end of the housing is secured to the handle, and the lower end of the housing is able to form a rigid, detachable connection to the neck extension; and an electric heating circuit that passes through the electric circuit housing, such that a heat generating portion of the heating circuit emerges from the lower end of the housing; wherein when the electric circuit housing is made to form a rigid connection to the neck extension, then the heat generating portion is disposed inside the applicator head; characterized in that the heating applicator system further comprises a sliding sleeve that covers the heat generating portion when the first and second subassemblies are not attached, and that is retracted into the heating circuit housing as the heat generating portion is inserted into the applicator head. a disposable first subassembly that comprises: a reservoir that has a top end in the form of a hollow neck, the neck having an upper orifice that provides access to the interior of the reservoir; a hollow neck extension that is connected to the neck of reservoir in a detachable and reattachable manner, such that the upper orifice of the reservoir is surrounded by the neck extension; and an applicator head that depends from the neck extension and passes through the upper orifice and into the reservoir, the applicator head comprising: a hollow stem that has an opened proximal portion and a closed distal portion, wherein the closed distal portion supports a working surface; a reservoir that has a top end in the form of a hollow neck, the neck having an upper orifice that provides access to the interior of the reservoir; a hollow neck extension that is connected to the neck of reservoir in a detachable and reattachable manner, such that the upper orifice of the reservoir is surrounded by the neck extension; and an applicator head that depends from the neck extension and passes through the upper orifice and into the reservoir, the applicator head comprising: a hollow stem that has an opened proximal portion and a closed distal portion, wherein the closed distal portion supports a working surface; a hollow stem that has an opened proximal portion and a closed distal portion, wherein the closed distal portion supports a working surface; such that, when the reservoir, neck extension and applicator head are assembled, the interior of the reservoir is sealed off from the ambient environment, and the working surface of the applicator head is immersed in the reservoir; and a passage exists through the neck extension, and into the closed distal portion of the applicator head; and a reusable second subassembly that comprises: a hollow handle having a proximal end and an opened distal end; a power source located in the handle; a hollow, electric heating circuit housing that has an upper end and a lower end, wherein the upper end of the housing is secured to the handle, and the lower end of the housing is able to form a rigid, detachable connection to the neck extension; and an electric heating circuit that passes through the electric circuit housing, such that a heat generating portion of the heating circuit emerges from the lower end of the housing; a hollow handle having a proximal end and an opened distal end; a power source located in the handle; a hollow, electric heating circuit housing that has an upper end and a lower end, wherein the upper end of the housing is secured to the handle, and the lower end of the housing is able to form a rigid, detachable connection to the neck extension; and an electric heating circuit that passes through the electric circuit housing, such that a heat generating portion of the heating circuit emerges from the lower end of the housing; wherein when the electric circuit housing is made to form a rigid connection to the neck extension, then the heat generating portion is disposed inside the applicator head; characterized in that the heating applicator system further comprises a sliding sleeve that covers the heat generating portion when the first and second subassemblies are not attached, and that is retracted into the heating circuit housing as the heat generating portion is inserted into the applicator head.