Salt-cellars were the most frequent suggestion, although almost as popular were paddling pools for pet spiders, mice or lice. Alexandra Harley and Martha Burke point out the value of navels in Subbuteo golf, or for storing fluff from the tumble-dryer, or a mould for making icing whirls for small cakes.
Stuart Cockerill suggests the navel as a rest home for earwigs with vertigo, or somewhere for naturists to keep loose change. Along similar lines, Chris Bell advises the use of the navel as an ashtray for nude debating contests, or an emergency exit for psychic detritus.
Luela Palmer finds hers handy for the storage of chewing gum. D M Gaunt, however, warns against this: 'It brings tears to the eyes when making a withdrawal from the depository.'
The juice squeezed from a navel may be used for invisible writing, showing up when heated, says Karyn Vitali, proving the point with a faint, although probably microwaved, signature. Her boyfriend, she says, wanted to eat his ice-cream off her navel, but she refused to let him add chocolate sauce.
The navel as a socket was utilised by Clare Smith in two ways: either for an inconspicuous spy camera or a small torch, which is particularly useful for reading in bed.
'It has long perplexed me,' writes Paul McHugh, 'that men have navels as well as women. Oh sorry, I think I mean nipples.' Having now realised that men have navels as well as nipples, he points out the function of the navel - indispensable for models and streakers - to locate the centre of the body. Mystics, he says, can produce an 'ohm' sound from the navel.
Paul and Steph point out that ear- lobes fit exactly into navels, while D Godfrey sees the navel as a receptacle for ear-wax, both of which bring us neatly heading in a lobewards direction. D M Guest is convinced that he remembers seeing an advert for the Van Gogh Society in the Artist, which appealed for donations of unwanted ear-lobes ready for their hero's second coming.
'People with extremely long earlobes,' says Michael Rubinstein, 'often use them to tickle their navels in order to stir from a state of too-long contemplation.' He also reminds us of the ancient art of character reading and prediction through Navelistry. 'The ear-lobe is a channel to the heart,' says Nicholas Gough, romantically. It is a 'Zen mind- portal in Eastern religio-philosophy,' says Rufus J Sanders, contemplatively.
The 'most bizarre thing' David Nicholls can think of for an ear-lobe is 'to make a hole in it and dangle a piece of metal from the hole.' Less bizarrely, he says, you can sever the ear-lobe, attach a handle, and use it as a very gentle pestle for grinding fluff in the navel.
The question of ear-lobe evolution has been exercising some of our finest minds. Stuart Cockerill says there are two schools of thought: 'The first claims they are adaptations to protect juvenile ears from the effects of clipping by policemen; the second inverts this, suggesting their prime purpose is to protect constabulary knuckles.'
Rufus Sanders, however, believes that 'the ear-lobe was an evolutionary afterthought, an offshoot from the largely successful camel project. Fat laid down in the lobes has been shown to sustain the human being at times of great emotional stress and little or no food, such as student parties.'
'Pierced ears,' say Alexandra and Martha, 'can hold a rolled-up copy of the Independent', while the bits removed on piercing make excellent croutons. Finally, they suggest that a washing-line may be suspended between two people with pierced ears - ideal for windless days. Pierced ear-lobes, say Fiona and John, make excellent Channel tunnel advertisements, or tethering points for prisoners.
'I hope I am not too late,' frets Gilbert Wood, 'to share with other readers my own alternative use for ear-lobes. For some years now, I have been using them - filled with air - as buoyancy aids when shipwrecked. This is an inexpensive and practical way of saving life at sea which should be more widely known.'
Next week, we shall be reporting on ideas for redeployment of the royal yacht, Britannia. Meanwhile, we should like to hear your ideas for using all the apostrophes ungrammatically placed on fruiterers' stalls and elsewhere. Ideas to Creativity, The Independent, 40 City Road, London EC1Y 2DB.