The Owls of Athens Bagpuss : Season 1 Episode 2

Emily brings in a very old, very dirty dirty bit of rag, which Yaffle can see no value in (as ever), the mice start to vigourously clean the cloth before being stopped by Madeleine. She implores the mice to be more gentle with the cloth, and they clean it lovingly, to reveal an old cushion cover with an owl on it. The mice run away, scared by the owl, but come back when they realise it isn't real..