When heartsick bachelor Keith Ruff was extravagantly wooing his beloved awhile back, one of his ploys was to hire a clown.

The girl had refused all previous amorous advances, but how could anyone resist a clown?

Ruff sent his limousine to collect some gifts and the clown--Becky Santora ("Rainbow") of Bethesda--and deposited her on the young lady's doorstep.

"I knocked, cleverly turned my gloves into a bouquet of flowers, and was politely asked to get lost," recalls Santora.

"Most people are happy to see clowns. They tell me I've brightened their day," adds Santora, one of the professional clowns in the area.

Clowns are in great demand (and charge $40 and up) for children's birthday parties, fund raisers, company picnics, embassy parties, pool parties, family gatherings, 40th birthday parties and even for bar and bat mitzvahs and church services.

Like everyone else, clowns have specialties. Some devote their energies to children, to the ministry, or to circus work. Some combine juggling, ventriloquism, magic or puppetry with clowning. Santora, who is also a magician, is an expert in hospital clowning, and has given lectures to clown clubs on the subject.

"I've always been a clown," says Santora. "When I was born I weighed 5 pounds, 5 ounces, and the 5 ounces was pure red nose."

"I can't resist entertaining people. When I go to the doctor's office with my kids, I pull some balloons out of my purse and start shaping them into animals."

Santora ("clowns are ageless") began her training by learning magic. After that, she attended several conventions and workshops on clowning and gradually developed her "Rainbow" clown personality.

"To develop your clown character you have to know where he's coming from," says Lucille (LuSilly) Ellis, 34, of Manassas, who stresses history and ethics of clowning in her classes at Wakefield Recreation Center, Fairfax, and Northern Virginia Community College, Manassas.

"People interested in clowning must also know the ethics, which are very strict," says Ellis. "For example, a clown must be clean, and must refrain from alcohol, tobacco and profanity while he is in costume, or 'in clown.'

"Most people don't realize that clowning is a very controlled art."

Clown characters in the United States today are variations of three basic types whose makeup and personalities have been set by tradition.

Bill (Shortcake) Straub, 63, of Silver Spring and president of the Maryland/D.C. branch or "alley" of Clowns of America, makes these distinctions:

* The Auguste--Mid-19th-century Italian or German origin. "The buffoon, the troublemaker, the butt of all jokes." He falls down a lot and always gets the pie in the face. His makeup leaves some skin tone showing and he is likely to wear a wig, oversized shoes and colorful clothes.

* The White Face--"The elegant, clever, better-looking clown of French origin 1800s . He is generally talented in some area, such as juggling, music or mime." He throws the pie. White makeup covers all exposed skin. His face is highlighted with color, and he wears a skull cap or tiny hat, but no wig.

* The Silent Tramp--Born during the Depression. "The dignified, well-educated, down-on-his luck gentleman. His clothes are always clean and patched, but never torn. His makeup resembles soot collected from riding the rails, but the eyes and mouth are white as he always washes the soot away." Originated and popularized by Emmett Kelly, the only American-born clown character.

"I was definitely unfunny as a kid," says Marsha (Modine) Gallagher, 29, of Annandale. "But when I was in high school I began to notice that people laughed at things I did. I thought 'If they're laughing now and I'm not even trying, how would it be if I tried?' "

A friend suggested she run away and join a circus and the idea never left her. After graduating from college, she did just that.

For her last job as an "advance clown" for Circus Vargas, she was sent to each town a few days before the circus' arrival to entertain at nursing homes, hospitals, children's groups.

The seasonal nature of circus work, low wages and the cost of providing "your own transportation" led Gallagher to seek a more conventional job: as a clinical technician with a group of orthodontists. She now works occasionally in the area as "Modine."

"Clowning is the hardest job I've ever had," she says. "You are continually on the spot and people's expectations are high. You have to be on your toes all the time."

When "in clown," the Clowns of America Code of Ethics requires clowns to act the part. This can mean juggling the oranges in the supermarket on your way to pick up a quart of milk. Or pumping hands at midnight April 15 at the post office, which Gallagher--coming right from a job--wound up doing.

"Everybody has to pay taxes," she quipped to incredulous onlookers.

A sense for people, the pranksters agree, is the clown's most important attribute. "You can't comb every bald head with your giant plastic comb," says Leslie (Flower T. Clown) Homann, 30, of A Clown Company, Gaithersburg.

"A good clown gets inside people's heads and knows how to entertain them. Clown humor is clean, gentle, fun and never threatening.

"Clowning is a great way for shy people to come out. It allows you to take on a new personality, and gives you a license to do many things."

"You are really amplifying yourself," says Gallagher, "not hiding behind a mask."

And all clowns agree: There's nothing worse than being upstaged by an elephant, or being stopped by a policeman while "in clown."

When Flower was pulled over for a minor traffic infraction, the policeman took one look at her and called into his radio, "Oh my God, I've got a real clown here!"

Fellow policemen raced to the scene, sirens blaring, to find him chatting amiably with the diminutive Flower.

A Pennsylvania State policeman refused to give Charlie (Chuckles) Fowler, 58, of Upper Marlborough, a ticket for speeding on the Pennsylvania Turnpike. "I couldn't stand to see a clown cry," said the officer, handing Fowler a mere warning.

Fowler, recently retired from Navy Department Headquarters, now devotes much of his time to being a clown for both children and adults.

Fowler says children are more likely to stiffen when he arrives if he is not "in clown." As Chuckles, "I'm greeted warmly."

"A clown is immediately trusted and loved," says Homann. "It's a universal sign of love and happiness."

Homann describes "inner clownness spirit"--not the costume--as being the essence of a clown.

"Clowns are the best medicine for society because they reduce tension."