Help! Wood large Tool box trunk chest.

I purchased a lot from an auction, It contained multiple old wooden tool boxes. I can't seem to find any info on one similar to this. My biggest problem is the combination lock is LOCKED. I have no idea what's inside it is super heavy. Does anyone know how to pick this lock without damaging the chest? As well as anyone have info for this trunk. It is pretty big, the original owners where from New Hampshire. And most contents of items with this where from 1800's era. I just can't find anything similar to it. Thanks Brandi