Elliptical galaxies have hot X-ray emitting atmospheres but practically no cold gas, so it came as a surprise that they are often 60 um and 100 um IRAS sources. There are two likely explanations for the origin and heating of the dust that emits this far infrared radiation. The dust may be in a low-mass disk of neutral gas near the center of the galaxy and is heated by starlight. Alternatively, the dust is shed by stars during stellar evolution and heated by collisions with the ambient hot X-ray emitting gas. In the later model, the far infrared emission will appear extended in the closest large ellipticals, while in the former model it will appear point-like at ISO resolution. We propose 60, 90, and 180 um mapping of the four nearest large ellipticals with hot atmospheres to determine if the emission is extended, and whether the temperature gradient is consistent with the electron collision model.