A friend of mine in the UK used to look out for the clubcard deals in Tesco, where they offer you tons of points on obscure products they want to shift. He'd then buy, for example, two trolley stacked full of sugar, or yoghurt coated muesli bars, or dogfood, or whatever it was, for say 250 quid. That would give him enough clubcard points to convert to airmiles to get a business class return to Rio, for example. He'd then just give the food away or throw it out.