Heat warning devices directly applicable to hot surfaces

Heat warning safety device comprising thermochromic ink or epoxy in the form of a heat warning symbol sprayed, stamped, stenciled, silk screened, embossed to the hot surfaces of appliances. The device is invisible when cold and is visible when a threshold temperature is reached. In a second version when cold the device shows only the outline of the warning symbol and when hot shows the full symbol. A plurality of these versions of the devices can be placed on various parts of appliances to maximize the effectiveness of the warning system and to tailor it both to children who need guidance as to where to look for said symbols and to adults as to whom the impact is greatest when the warning symbol appears from a point of invisibility. Alternatively, the warning symbol appears on the lip of a mug and advertises the staying power of the hot liquid therein.