These are the type of thing you see reduced in supermarkets as they go past their best. Roasting them and storing them is a great way of preserving very cheap ingredients. Rub them with olive oil and roast in a hot oven until the skin is black and charred. Once cooked, place them in a bowl, cover with clingfilm and leave them to steam for 10 minutes. Once cooled down, peel off the skin. Don't run them under water as you'll lose the roast flavour - if a bit of the roast skin is left on them, don't worry too much. Place them back into the bowl and cover with cider vinegar. Press the peppers down to make sure any air is removed. Allow to stand for another 10 minutes. Pour into a sterilised jar and cover with olive oil - add a few black peppercorns to help them on their way. These peppers can be quite strong to eat on their own - the vinegar does have a kick. But - they are perfect for adding to dishes that will take their stronger flavour. I added a few, chopped up, to a beef chilli I cooked recently - the fruity vinegar flavour complemented the spiced beef perfectly.