For centuries, whales have been viewed as valuable commodities, with nearly every part of the animal used. Whale oil was a valuable commodity during the 18th and 19th centuries. It burned brightly and cleanly which made it an excellent fuel for lamps. Its smooth consistency and resistance to gumming made it ideal for lubricating machinery, especially delicate instruments like clocks and watches.
WWI increased demand for whale oil and increased the price substantially. The oil was used to make glycerol in order make explosives. Whale oil was used to process jute to make fabric for sandbags too. It helped soften the fibres, making them easier to spin into yarn for weaving the bags.
A worldwide shortage of vegetable oils meant whale oil was widely adopted to produce margarine during this time. Britain declared whale oil critical to national defence.
The discovery of kerosene from petroleum in the mid-19th century provided a cheaper and more readily available alternative to whale oil. Combined with the increasing use of vegetable oils and the scarcity of stock slowly shifted the demand for whale oil.
Soap made from whale oil, South Georgia Museum