Toilet duck is still happily sold in The Netherlands. The Dutch name is 'WC eend' (WC stands for water closet). TV commercials for the product have disappeared quite a few years ago, but the product seems to have grasped a firm foothold in Dutch society.

The shape of the bottle is quite handy, as anyone who has ever had to clean toilet bowls can attest. The liquid is a mixture of chemicals that is able to pervade the outer layers of the toilet bowl itself.

Once, I left a sizable amount in the bowl, with the (quite stupid) idea that this would provide for some extra cleaning. After flushing, the bowl was filled with blue streaks of damaged ceramic. The streaks are still there for all to be seen and examined. Do not try this at home! (but maybe at your parent's house...)