The invention relates to a method for production of a metal strip from a strip (6), cast directly from molten metal (4), whereby a trimming of the strip edges (9, 9') of the strip (6) is carried out, characterised in that the strip edges (9, 9') are cooled before the trimming in such way as to render said edges more brittle than the rest of the strip (6). The invention further relates to a unit for processing a thin metal strip (6), arising from the casting of thin strips directly from molten metal, characterised in comprising a unit for the controlled, exclusive or preferential cooling of the strip edges (9, 9') of the strip (6).