Approximately how much would it cost to remove all the unexploded ordinance from Noman's Land?

>https://en.wikipedia.org/wiki/Nomans_Land_(Massachusetts)

The island is currently listed as a wildlife refuge, but IMO that's just an excuse to prevent curious visitors from getting themselves blown up.

I'm asking because I thought it might be a cozy little place to build a spaceport for smallsat rockets like Firefly. It's probably the only even remotely suitable location anywhere in New England.