hi guys, thanks for the suggestions and advice! i finally managed to open it up after some wd40 sipped in. i used a forcep that i sneaked out of my workplace operating room!
you all are right, the battery is leaking, there was some solid blue thing all over the compartment. i managed to clean it up, although, unfortunately, i accidentally pulled the battery contacts! darn this heavy hand! anyways, i will ask for a quote from a local shop for the repair. if it'd cost about a hundred, i think i will just get a dedicated light meter. any sggestion for a good one that can read incident and reflected light, in small package? maybe around $100+... thanks!