Steph phoned me with a cleaning problem - she wanted to know how to remove stains from her plastic kitchen sink without using harmful cleaning chemicals. I suggested that she cut a lemon in half, dip the cut half in salt and use it to scour the stain. The salt has a gentle scrubbing action and the lemon juice ought to bleach the stain away. It might take a few repetitions, depending on how bad the stain is, but it should have some effect.
The trouble is now I have a craving for margueritas.