Rats on ships were an unpleasant fact of life; they've even made their way into our language with phrases like 'the rats leaving the sinking ship'. This newspaper account of 29 September 1743 reports one rather drastic way of getting rid of them. There is nothing in the story to say whether the interested audience went on to adopt the method demonstrated. However, one imagines that the need to completely empty a ship, not to mention the risk of burning it along with its vermin, was enough to give pause for thought.
Last Thursday an Experiment for destroying Vermin was tried on board the Squirrel Man of War, in Deptford Dock, before a great Number of Merchants and Owners of Ships; the Vessel was empty excepting Ballast, on which was laid a large Quantity of Brimstone, Straw, and other Combustibles, which being set on Fire, the Air-Holes were then immediately stopp’d, and soon after open’d again, when, on going into the Hold, they found upwards of 2000 Rats that had been suffocated in a few Minutes.