Your once-shiny metal trays can look hideously dirty even when you've cleaned them. But not to worry - here's a five-step method to have them looking as good as new.
Pour white wine vinegar or apple cider vinegar into a spray bottle and generously spray over the baking soda and salt. It'll fizz up, but don't worry - that's the point.
Step five
Next use a heavy-duty scourer or steel wool and scrub like your life depends on it.
If the trays are just metal, without a special coating, then scrunched-up tin foil will work as well.
As you scrub with the scourer (preferably wet but wrung out), the ingredients should turn into a rough paste.
Work it into the pan for five or ten minutes - really put your muscles into it. Now, most of the dirst should wash off into the sink.