how to make green screen objects glow???

hey is there any way to make green screened object glow? for example if i have a ball and it is painted green could i use the chroma key to somehow give it a glowing orb effect? pretty much im trying to do a light saber effect with out doing it frame by frame. i was hoping that i could just get a green painted stick and use the chroma key to give it a glowing lightsaber effect. any ideas on how to make this work?