In 18th and 19th Century whaling the main products were blubber (the source whale oil) and the baleen from mysticete whales (mostly Right and Bowhead whales). The baleen in one of these whales hangs in two rows of plates from the upper jaws, and fraying of the keratinaceous material from the inner edges of each plate produces a fibrous filter that entraps krill from the water forced through the filter. In Right and Bowhead whales the krill is composed of small zooplankton (copepods) each the size of a grain of rice, or smaller. Consequently the baleen plates in these whales are more numerous and longer than in other mysticete whales. A right whale may have 400 plates on each side, up to 9 feet long, while a Bowhead whale's plates can be as long as 15 feet. Baleen is from keratin, the same protein that makes up our hair and fingernails, as well as the horn of cows and other ungulates. It has properties of elasticity, flexibility, and can be formed by heating it until softens and then subjected to pressure in a mold. It, basically was the “plastic” of the 18th and 19th centuries. It's many uses in the late 19th century caused its value to escalate so much that the it was worth up to $5 per pound to the whalers. And with a large whale having as much as 2000 pounds of it in the mouth, the value of the baleen far exceeded that of the oil from the blubber of the same animal. Baleen (the whalemen called it “whalebone” or just “bone”) was harvested by cutting though the bases of the two upper jaws behind the mouth as the dead whale tethered to the boat floated beside it. The entire upper front of the head was then winched aboard. In the 18th Century, Scottish, English, and Dutch whalers carried home the unrendered blubber and the ranks of baleen, to be processed ashore at the end of the season. In the spirit of enlightenment I'm including a couple of period figures (likely taken from "Diderot's Encyclopedia" in the latter half of the 18th century) showing the process of handling baleen in a shore based setting (a cooper's shop), and some of the tools and techniques used to fashion useful articles from baleen. Note the maul and wedge being uses to separate the baleen plates.