Once you have finished your shop-bought sliced bread, don’t throw out the plastic bag because you could reuse it in many ways. First, tip it upside down and shake over the sink or bin to remove all crumbs then, store in a small container. I store mine in a plastic pint glass. You might also want to leave the bag open for a few hours to remove any moisture (which would lead to mould growth after a few days). I use my plastic bags for packed lunch sandwiches, home-made bread, as dog poo bags, as a compost bin, to replace clingfilm, etc. Could you suggest any other uses??