It is a tradition with agit-prop origins. In New York, in the early Sixties, the pioneer mail artist Ray Johnson plotted to cause chaos by posting thousands of bricks without postage stamps, addressed to art galleries, concert halls and museums that he despised, and with return addresses selected from the same hate list.
Today, relations between mail services and mail artists are less fraught. The Royal Mail seems willing to play along, with exceptions. In addition to a prohibited list - which rules out the sending of explosives, aerosols, rat poison, matches, obscene publications, counterfeit banknotes or what is described as "filth" - a Post Office spokeswoman told me that postal workers were relied on to stop mail that seemed likely to harm them, the recipient, or other mail. So perhaps I was lucky to receive the log and the sharp- edged picture frame, both capable of denting or impaling conventional buff paper packages unless carefully handled.
Indeed, one item - a pair of chopsticks that had been mailed protruding from its paper sleeve but securely glued to it - arrived in a Royal Mail plastic bag with a note admitting damage and offering "sincere apologies" and an investigation. "Did these cause you any bother?" I asked my postman. "No," he said, "we all had a good laugh."
It takes only a few dozen faxes to organise an art mailing. The painter Peter Liversidge faxed my address and fax number around his network of collaborators, who faxed me descriptions of what they had mailed, so that I could check whether or not they got through. Benny Feuerstein, aged seven, faxed a drawing of his orange which then arrived in the mail unwrapped, delicately postmarked and undamaged. Marilyn Dammann's lemon made it all the way by airmail from Baraga, Missouri, US. But it was desiccated, rock hard, and in a string bag. A bit of a cheat, that. As was another sender's hen's egg - pierced, blown, addressed, and rolling around in a transparent plastic box.
The only missive that failed to make it was a wad of bubble gum in the shape of a CD. Its sender omitted to put a return address on it, so it is presumed destroyed or eaten.
One of Liversidge's biggest coups has been successfully to mail from Exeter to London all 26 pieces, separate and unwrapped, of a school chair. But his blown-up balloon disappeared without trace and his local Post Office would have nothing to do with his (empty) army surplus cylinder marked "Dangerous Explosives".
Liversidge once mailed unwrapped sticks of firewood to an impoverished friend and was then mortified to discover that he had burned them. They were art, for goodness' sake.
Liversidge exhibited his mailed chair at the Spacex Gallery in Exeter. Mail-ins are frequently exhibited. The artist and teacher Julia Tant, who sent me the coconut, exhibited the 250 responses to her mail-in on the theme "Cooltan" at Brixton Library last year. A Russian entry showed a bottle of beverage cannily crafted with a "Cooltan" label.
Are mail artists cranks? Liversidge's fax-out located a few. One participant, in Manchester, ignored the request for unwrapped items and sent five separate envelopes containing neatly printed and counterfoiled tickets for "one-way time travel", both backwards and forwards. I distributed the backwards ones in my local pub, telling regulars that they entitled them to drink after hours. (Typically, mail-art envelopes are plastered with stickers and rubber stamps, as popularised by Ray Johnson, with inscrutable slogans such as "reinvesting in activism" and "sensing the heartbeat".)
One of Britain's most creative mail artists, Nigel Bents, at Chelsea College of Art and Design and the London College of Printing, has published a guide containing photographs of his most celebrated raw-object mailings. They include 2ft pieces of driftwood, stones, eucalyptus bark sent from Australia, dry bones, a crab's claw clutching a postage stamp, a tiny knitted teddy bear with the Royal Mail's 20p teddy-face stamp appropriately affixed, and a postmarked but unruffled white feather.
Participants in themed mail-ins are usually offered a free catalogue of all the entries received. Bents goes further. He holds "post and host" evenings. Those who received his stamped-addressed bits of string marked with stations on their London tube line followed instructions on the attached label to take the tube and meet at the Royal Festival Hall for a drink.
Having introduced his students to the mail- art form, Bents endured the embarrassment of being handed, by his department's secretary, a stamped-addressed dirty comb that one of his students had picked from his pocket.
His only challenge from the Royal Mail came after he had tampered with the 1996 European Championship football stamps, substituting the Queen's head for those of goal-scoring footballers. Having posted them on first-day covers, he found the calling card of a Royal Mail investigating officer on his doormat. Days later, his two letters were delivered back to him in a Royal Mail envelope, ignominiously folded.
Some of Bents' tips: strange, unwrapped objects stand a better chance of being accepted for delivery if you pop them in a postman's sack as he makes a collection on the customers' side of the Post Office counter. Put elastic bands round objects: postmen love elastic bands. Mark them "postal novelty" - it seems to legitimise them. Avoid sending address labels with nothing attached; they get stuck in the sorting office awaiting non-existent packages.
Michael Leigh, who sent me the chopsticks, the wooden coat hanger, the squashed beer can, a plastic sword and a CD, all bearing his signature sticker "A1 Waste Paper", has discovered a mail artist who predates Ray Johnson. He was one Reginald Bray, who featured in a series of Churchman's cigarette cards, "In Town Tonight", of 1938. His card records some of the self-addressed objects that he began to post in 1898: a shirtfront and collar, a bowler hat, a shoe, a bicycle pump, and a turnip with the address neatly carved into its flesh. Precisely who Reginald Bray was, and whether any part of his collection has survived, though, is not known. Answers on a turnip please.