THE “humble stale loaf” can be turned into biofuel without the aid of green technology (Comment, 5 April).

It must first be toasted, or sliced up and soaked in milk with added dried fruit, or served encapsulating cool summer fruit or hot winter apples, or diced and fried in butter for soup, or finely grated for fish, croquettes, etc; and though assembling the other ingredients for cassoulet may present a logistical problem, at least you’ll have the topping handy.

William Dixon Smith, Welland Rise, Acomb, York.