Spare any change, monsieur/senora/ mein Herr? If you're in euroland this summer, just check what you are handing over. You may be being a lot more generous than you think.
In Britain, we cling on to our current bland coinage, fearful of the future, guilty about the past. We scarcely glance at our diminishing tokens of exchange, yet we say we are slavishly attached to the relief of our German monarch, content to regard ourselves as subjects - though, in truth, we have all been citizens for 20 years or more, at least according to our passports.
In the countries of euroland - including such statelets as Monaco, San Marino and the Citta del Vaticano - things are very different. There, the new coinage, all 120 pieces of it, is a constant and tangible reminder of unity, the way forward, the future. Although the notes issued by the European Central Bank are the same throughout euroland, coins - in denominations of one, two, five, ten, 20 and 50 cents, and one and two euros - are minted by individual countries with a common obverse and a national reverse. Euro-citizens feel genuine pleasure when they find Portuguese castles in Potsdam, Mozart in Milan, a Celtic harp in Athens.
There was a similar pleasure to be had from Britain's "old money". It was not unusual to find a Victorian penny in one's loose change, rubbed thin by a century of fingering. Edward VII florins, George V tanners, a bob bearing the bust in relief of George VI - all spoke of something more than mere money. But that was looking backwards, nostalgia tinged with increasing remorse, and it died along with £sd in February 1971. The future beckoned and, a couple of years later, we broke the chains of all that old history and bounded free through the open doors of Europe.
What a shame that the confidence of 30 years ago has given way to such small-minded insularity. Still, for a fortnight or so each year, many of us visiting Austria, Belgium, Finland or France, Germany, Greece, Ireland or Italy, the Netherlands, Luxembourg, Portugal or Spain can taste the excitement of a future that could yet be ours, and imagine what it would be like if the 25,000 sets of British euro coins minted experimentally by the International Numismatic Agency Ltd - with the Queen's head on each one - were the currency of the realm.
But wait, there's more. Just as some of us checked our change before 1971 to see if we had an old silver sixpence, worth several quid to a collector, or a 1952 penny (because the old king died in February that year, not many bearing his bust were minted), so euro-citizens double their delight with their new money by scanning their cash for, say, a one-euro coin bearing the head of Pope John Paul II. One collector in France will give you 130 of his "liberte, egalite, fraternite" euros for your Vatican example, so rare are the coins that made it into general circulation rather than straight into the hands of dealers.
Watch out, too, for Finnish one- and two-cent coins. Finns have more of an aversion than most to small change. They minted only four million of these coins compared with five and a half billion produced by, say, Germany. And they are not going to produce any more, as Helsinki has passed a law rounding all prices to the nearest five cents. With their reverse relief of a traditional heraldic lion, these coins fetch up to 600 times their face value.
Then there are the Spanish two-euro coins on which the length of King Juan Carlos's hair varies, and the discrepancy in the number of stars on Belgian cents. All good fun, but not as much as being in the great project itself - a project becoming greater still, with or without Britain, as Europe thrusts itself towards the Urals. Poland, Hungary and the Czech Republic could soon be adding another 24 coins to the pot. Even Switzerland is making overtures to Brussels and Frankfurt. If the green light is given, tiny Liechtenstein, economically integrated with Switzerland, will join and, sooner or later, the head of Prince Hans-Adam II will turn up in Antwerp or Ajaccio.
Much of the currency produced by the statelets is sold, like their postage stamps, as souvenir packages, adding revenue to government coffers. That is something Andorra, another statelet in euroland, would like to do. No, says the European Commission, you can't mint your own euros until you clamp down on smuggling. A great deal is at stake, but would Andorra's coins show the president of France or the Spanish Archbishop of Urgell, who govern jointly? Check your change.
Michael Holland is comment editor at the Observer