To this day, metal remains the most popular material for manufacturing various tools. But, its era is apparently coming to an end, because, with even the most basic knowledge of chemistry, it is possible today to make anything from anything. A YouTube video hosting user, with the nickname Kiwami Japan, can serve as an example with the knife he made of ordinary foam plastic.
First, he made orange oil and used the liquid to dissolve the polystyrene foam. The resulting substance was treated with alcohol to remove air from it and then used as the knife’s basis.
The exotic knife’s quality is, of course, inferior to that of its metal analogues, but it can usable, anyway. Thus, an ordinary amateur inventor has demonstrated that with knowledge of science nearly everything is possible.