No greasy, kid stuff for John Travolta. For the movie "Grease," Travolta used about four tubes a month of Groom and Clean or Alberto VO5 for the '50s greased-back hair. But for his own look, according to Michelle Serena, 26, who has done his hair for five years, "he doesn't want to bother much with his hair. He just doesn't want the hassle," she says.Serena's salon is in West Hollywood and called Eric Serena, the name of her husband and partner. She's 26, and counts as clients, along with Travolta, Marsha Mason, Gene Simmons (Cher's latest flame who is head of the group KISS) and Dr. Timothy Leary.

Travolta's hair was the shortest for "Saturday Night Fever," with no sideburns at all. The greasy slicked-back hair for men was on the scene in LA long before the movie "Grease" or the '50s fashion revival, says Serena. She pegs it as inspired more by Robert Nero in "The Godfather" than any '50s retro clothes. Now a lot of women, including Serena herself, are doing it, but always using one of the water-soluble products. "No one wants to hit the pillow with that stuff still in his hair," says Serena.

Serena expects straight layered hair to follow the frizz. Her clientele is always ready for a change. "Change is fun. Why bore the world trying to look like someone else," she says. "If you can't have fun with your hair, wear a hat." She does outrageous things with color for the adventuresome clients, good workable, easy-to-handle cuts for the others. "We're coming to a period of pure theater for the hair, from the turn of the century to the 1980s . . . because people will stop being afraid to have fun with their hair. I hope."

Will the movie "Grease" do for the '50s look what "Saturday Night Fever" did for the disco suit? Probably, and that's not much. Of course, there is already a jeans jacket and jeans with a Grease patch by Sedgefield at Woodies. There are already bobby socks and flowered shirts revived from the '50s; women are into pegged pants, there are some circle skirts around and women are wearing men's white dinner jackets. But things never come back the way they were the first time around. "The young customers who never got to wear these things in the 1950s really love all these looks," says Nancy Chistolini, fashion director of Woodies.

The great wedding dress hijact is really a hijinx. According to one report, a wedding dress thought to be the dress Princess Caroline will wear for her wedding to Philippe Junot was smuggled out of the atelier of Christian Dior, then photographed by the German magazine Bunte in a picture, that through trick photography, made it look like Princess Caroline was wearing it. "Nonsense," says designer Mare Bohan about the story. The dress mock-up was styled after a wedding dress from the couture collection, the traditional finale for the fashion show, with not connection to the dress made for Caroline.

Bohan has made dresses for Caroline and her mother Grace Kelly, for the ball which takes place two days before the wedding, the civil ceremony and the formal wedding. Caroline's two wedding dresses are white, otherwise all the other dresses are in solid pasted shades, including apricot, yellow and pale gray silk georgette.

The wedding dress design is very simple, says Bohan, who also says that Caroline's shoes are medium height so that she doesn't tower over the groom and the simple headpiece will be trimmed with little fresh flowers.

Bohan and two others from Dior, a fitter and the vendeuse (saleswoman for the couture) will be in Monaco for the wedding celebration.

Apparently life as a foreign correspondent is not all Graham Green intrigue and suspense. There are rough spots - such as the face that must endure strong desert sun and vicious mountain gales.

Hence this desperate plea from NBC's John Cochran: "SEND JERGEN'S FOR MEN!" implored Cochran, who is based in London, but travels across the continent.

Easier, alas, said than done. Jergen's still makes the special moisturizer for men, bottled in macho mocha, but the product is scarcely available in these parts.

The product has a small but loyal following, says a Jergen's spokesman, adding, "But most men are perfectly happy to use whatever lotion their wife uses."

It's as essential for a picnic as a blanket and bug spray - the wine belt with a buckle that is also a wine opener.Works as a bottle opener, too. What's best about it is that without the gimmick, it's a handsome inch and a half wide brown leather belt with sleek silver metal buckle, with no clue that it hides a gadget. From the Wine Belt Co., 10 greenfield Drive, Moraga, Calif. 94556. $18. Send belt size.

Chacun a son gout. Father's Day gift department . . . clear vinyl jogging shorts from Neiman-Marcus. Among the gift givers - Pearl Bailey bought two pairs.

Even before the summer clothes have been brought forward from the back of the closet and new summer dresses bought by a lot of people, stores are already into pushing clothes for the fall in their ads as well as on T-stands and on racks in the store. We know it helps to be the first on the block with a new look, but from readers we hear that they wish stores cared equally much about having the clothes in stock when we really need them. Like bathing suits midsummer when it becomes necessary to buy a replacement.

Battle for Washington's big bucks (cont'd). Who's got the best mink coat? David Wolfe of Neiman-Marcus says he does because he bought the first bundles of black willow mink skins offered at the recent Hudson Bay Co. sale. Hudson Bay offers its best bundles first, says Wolfe, and they really know.

Ernest Marx of Saks Jandel says he's got the best mink skins because he paid the most for them ($360 per male skin) at the very same auction, even though they weren't the very first bundle offered. Whatever, Wolfe admits that all the black willow produced by John Adkins is good. "Even the worst bundle is like buying the worst Mercedes, it is still a quality of the best," says Wolfe. (Neiman's produced to dollar, $300 in fact, for the top females.) The Neiman coat, available in August, will sell from $18,000 to $20,000. The Saks/Jandel "best" will be about $25,000.

By the way, these mink pelt prices are the world's highest since 1966.

We thought we might be saved this season from all the plaid pants of the past. But there they were, out loud, first at the Georgetown University reunion and again recently at the D.C. Banker's Convention at The Home-stead. Both groups were heavy on madras plaid, the bankers heavier still in their printed polys. Anyone looking for an alternative, there are many khaki, poplin, seersucker, white duck, silk.

It is not only John Travolta's hair they are watching out there. A caller recently wanted to know who does Merv Griffin's hair and how. "I'm a 63-year-old man and I haven't had my hair cut since last summer and it finally dawned on me - what I want is to look like Merv Griffin. Help." Ciro Alvarez of Ciro's in L.A. does Griffin's silver-gray hair once a month. (He also does Steve Allen and Frankie Avalon.) Griffin gets a contour cut, which can be worn lots of different ways and always looks full, says Alvarez. Specifically, it is a 1 1/2 inches in front, two inches longer in the back. "It looks like fur on his head, it is so full," says Alvarez. Griffin washes and blow dries his hair daily.