I carry around a small notebook (usually a 48 page Field Notes) for short fleeting notes. Later I copy them into my commonplace book/zettelkasten/digital garden and expand up them.
Waste books were used in the tradition of the commonplace book. A well known example is Isaac Newton's Waste Book (MS Add. 4004) in which he did much of the development of the calculus. Another example is that of Georg Christoph L