If they are really very very blunt, it may be a good idea to have them professionally sharpened and then keep them in trim yourself afterwards.
Anyone else remember the guys who used to come round on a bike with a knife sharpening thingy on the front? Also the rag and bone men with a horse drawn cart. Used to give out goldfish in little plastic bags in exchange.
Pete.8 In the days when there were four dollars to the pound, the old 'half crown' was usually referred to as 'Half a dollar' - or 12.5p in today's money.