7. Wheat straw.
In the past, at the end of a growing season when you were left with wheat and straw, you used the straw for animal bedding and thatching roofs. The straw from today’s wheat isn’t long enough for thatching roofs, though, and for years, farmers would burn it as waste. It can be used in various ways including in biofuels and biogas and in making composite lumber. There are even a handful of companies making drinking straws from straw and charging an outrageous price for it.