I’m used to cutting the black spots off a potato, however, if I boil them with the skins on and mash them with the skins, I won’t know if there are black spots. Are they OK to eat?

Black spots in potatoes are mostly attributed to internal bruises or the result of sugar concentrations brought on by any of several pre or post-harvest conditions and are generally harmless. However, the black spots could also be an early concentration of decay. Again, probably not entirely harmless following the cooking process but I recommend not taking any chances and cutting and discarding any such obvious discoloration. Idaho potatoes are very economical so whatever waste exists in skinning or slight defects is a minimal sacrifice– while the nutritional and heart-healthy attributes are substantial.