Are these blue spots on stove coil cups poisonous Verdigris?
Try a magnet - dollars to doughnuts, those are somewhat peeled and rusted chrome plated steel, and the blue is a normal steel oxidation color, and not toxic (also, were you planning to drip food down there, scrape it off and then eat it? If not, nothing to worry about regardless.) They are stunningly unlikely to be copper, though there may be a minuscule amount of copper plating as part of the chrome plating process

This is reinforced by the purple color, which is a slightly different temperature in the steel oxidation colors (we use them for determining temperature when tempering hardened steel.)



Image from Maille Artisans International League website

While you could waste money and effort replacing them, you could also make them more efficient (reflect heat better) and easier to clean by applying aluminum foil to them (shiny side up - you want to reflect as much heat as possible.) As a side effect this would also contain the non-toxic steel oxidation. When something is too badly burnt onto the aluminum foil, remove it and replace with new foil.  Mold the foil to the pan, wrapping over the edges - cut stars in the openings and fold the cut parts onto the backside.

FYI - stainless steel will also blue, at slightly different temperatures.