Probably,but I doubt they would be kind to your bore.
White Phosphorus and Magnesium are the usual fuel in flares. Both burn very hot, much hotter than gunpowder, and my guess is there would be increased oxidation and maybe extra wear at the forcing cone and choke.
IIRC, the cleaning drill for the old MM79 included flushing the bore with water to neutralize and remove corrosives. Maybe someone else had more current info.