It's reportedly in a cave accessible only at low tide. (I only have modest swift-water experience, but that's terrifying.) Of the three options you list, the only possibility would be a boat, and it's probable that the space is too restricted to get a large enough boat and equipment to move a shipping container in. And, it's a cave, so going in from the land side would probably require mining and still be dangerous.

If you just want to prevent Garfield pollution, it would seem like the best option would be to use explosives to close the cave and pretend it never happened.