I wish I had got back to you sooner.
I took a pair of salad tongs and removed them from the tub and left them on a short brick wall. It rained heavily that night so I wondered what would happen - I had it in mind that snakes might come out of them or something like that.
What was really odd is that they turned out to be bon bins - you know those toffee sweets with the flavoured sugar coating! I couldn't believe it. None of us have ever brought those sweets into the house, and how they got there to this day remains a mystery.