So you're looking to change your image, break out of that gray-flannel life-style, experiment a little? Maybe you should pop over to London, where Sotheby's auction house is holding a spectacular fall clearance sale this week. For as little as $1,000, you might pick up a pink hat crowned with a light-up model of the Eiffel Tower. Or how about some eyeglass frames shaped like grand pianos for maybe $700? In the $2,000 range, there's the black Lurex suit covered with Day-Glo cork balls sprouting from piano wires.

These sartorial treasures, along with racks of way-outfits, roomfuls of Art Nouveau furniture, important paintings, exotic and neurotic objets d'art, and a princely pile of baubles and jewels, have all been put on the block by one of the grand acquisitors of the 20th century, the pasha of pop-rock, Elton John.

"I'm impulsive," explains John, 41, in the preface to the four-volume, $75 catalog touting the collection. "If I see something I like, I just buy it." With 28 top-selling albums and more than 40 hit singles since 1970, John has had plenty of cash with which to indulge his shopping mania. Eventually, the accumulated goods got to be a burden. "He has simply out-collected his home's ability to absorb what he has purchased," observed Sotheby's British chairman, Lord Gowrie, after a visit to John's Windsor home (just down the road from Queen Elizabeth's place). "When I first went there, it was an Aladdin's cave, a magic toy shop, but hard to find somewhere to sit."

John's tag sale, which is expected to net about $5 million, caps his efforts to put his house in order after his life fell apart last year. In early 1987, British tabloids quoted his wife, Renate, denying that she'd had an affair with another woman while John was undergoing an operation on his vocal cords in Sydney, Australia. Then, that March, the day after Elton's 40th birthday, the couple announced that they were separating. "All I know is that I was terribly depressed," John told London's Sunday Mirror. "I was wallowing in self-pity, to be honest."

The cloud began to lift two months later, when he and Renate reunited. The title of his latest album, Reg Strikes Back, alludes to John's real name, Reginald Dwight, perhaps suggesting that he's at last comfortable with himself. Domesticity is now in the air. As he recently said, "It's time to make our house into a home to live in rather than a place for people to come and say, 'Well, that's nice, but where can I put my drink?' "