Can you sell aluminium cans and baked bean, tuna, ext tins to a scrap metal yard?
I think aluminium cans are your best bet as they normally have more recyclable value than steel (which is what most of your food tins will be made of.) You can find a list of places which will give you cash for your cans via the search facility on http://www.alupro.org.uk/cash%20for%20ca… Many collection points will probably only accept the cans in large quantities from you though so best to check with each centre before you start your collection.