If you stashed away your old punk T-shirt, that risque 1960s mini-skirt, a tight-fitting Biba floral number, flares or platform shoes, then you might be delighted to hear that wacky street fashion can fetch hundreds of pounds at auction.

Ms Suzette Shields, costume and textile specialist at Christie's, London, believes street fashion auctions are interesting because "it's everybody's past, basically, on display".

Its street fashion sales contains "more street wear than catwalk stuff" and includes "anything from the 1950s to the present day".

With street fashion auctions, a variety of people "come in off the street and think `My God, I've got things like that in my wardrobe'. You have children coming in and saying `My God, my parents were wearing that. How embarrassing'. But it's fun."

While most lots are "big-name designers" like Vivienne Westwood, unlabelled items are included if they're "wacky enough or interesting enough".

The sale next September includes: a full-length coat of tangerine plastic leatherette, guide price: £250£350; a full-length sleeveless dress of black plastic leatherette, guide £200£250; a Python Beauty case, guide £200£300; and a pair of yellow, green and red chequered shoes by JuJu Boutique, guide £200-£300. At a previous street fashion auction, a couple of pairs of plastic ankle boots by Mary Quant

who popularised the mini-skirt in the 1960s and designed "hardcore punk kind of things" made £600 each. One pair was coloured canary-yellow, the other was scarlet.

Ms Shields says: "There's a lot of interest in punk T-shirts. There's a really strong band of collectors for those Sex Pistols T-shirts and things." Initially, these wouldn't have cost "a great deal" but nowadays, in good condition, a single T-shirt could fetch £200.

The label Biba, which provided stylish clothes at affordable prices, is popular. "We have some devoted Biba collectors. There are some people who will wear all the Biba things from the 1970s." An early 1970s Biba full-length coat in brown, blue and green has a guide price of £300£500 in next September's auction. Biba clothing is "quite distinctive. They're very tight-fitting, with tight arms and narrow shoulders. They're very romantic clothes with floral prints; long, flowing things very, very feminine."

A pair of black sandals designed by Jean Paul Gaultier has a guide price of £200£300. "They're just black rubber and they're literally an imitation of Roman sandals. But they're quite good fun."

Swatch watches are also included. "They're still around. They're very, very collectable and generally fairly bright, some of them very garish watches . . . They would probably fetch more now than they would have done to buy new. Most of the ones we're selling are early 1990s, so they're not that old."

One Swatch watch called "Europe in Concert: MusiCall", designed by Jean-Michel Jarre with a sun and a jumping fish on the face and a musical alarm, has a guide price of £200£250.

Twenty ornate Hachi dresses with sequins and beads have guide prices of between £500 and £1,000. Dresses in this guide price range include a one-shoulder evening dress of steel grey satin and a sleeveless cocktail dress.

And, yes, there are brightly coloured ties including a psychedelic patterned "kipper" tie shaped like a kipper with guide prices of between £25 and £200. Ms Shields says: "They're very lurid in a way. They're turquoise and pink. There are big swirls. They would give you a headache if you look at them long enough. Ties are very collectable. There's a strong market for ties."