Through the Hatch!

When the children come to stay, the hatch between the kitchen and dining room comes into its own. Often a shop, today it was a library, so I had to choose my book, have it zapped (with sound effect) and was told to bring it back on time! This game went on for quite a while!
Yesterday W and his sister were playing shops, and we gave them plenty of change to use. However, soon they told us they didn't have any more money.
They had enjoyed putting the coins into a charity box we keep on the hatch, without realising that they couldn't get the coins out again!