For decades parents have been giving their children allowances. And for decades, allowances have been a cause of household frustration.

Although the allowance is meant to instill responsible money behavior in children, it frequently becomes the source of mismanagement on the part of parents.

When mishandled, the child's allowance can create selfishness, provoke anger and provide a weekly arena for parent-child struggles rivaling the Saturday night boxing matches.

That doesn't mean the concept should be abandoned. "An allowance," writes money expert Grace Weinstein in her book Children and Money, a Parent's Guide (New American Library, $8.95, 1985), "given consistently, is still the best way to teach children to manage money, to budget and to set priorities."

Parents first have to identify and avoid certain pitfalls:

*The allowance as a bribe.

While many children receive money for such chores as making beds and walking dogs, tying money to chores can lead to selfishness, according to many child-rearing experts.

"Giving a youngster an allowance just because he does what he's supposed to do implies he has no obligation to the family unless it feels good to him," says Montgomery County psychologist and family therapist Charles Simpkinson. "The child operates on the assumption that the family 'owes' him something. That system teaches children to be materialistic and manipulative."

Simpkinson's advice: Children should receive money for doing "above and beyond what's expected of them."

Adds Weinstein: While children should do chores and should receive an allowance, "Don't make one depend on the other . . . the result may be a child who won't lift a finger without pay. As Dr. Lee Salk succinctly sums it up: 'The parent who pays a child for taking out the garbage is creating a monster.' "

But as in many areas of child rearing, not all experts agree, thus adding to parental confusion. Voicing a common parental lament, Liz Weingartner, a guidance counselor at the Jewish Day School in Rockville and the mother of two teen-age boys, Michael and Eric, says, "I could never get that straight about whether allowance was free or was something you worked for."

Some experts -- such as Kim Long, a clinical social worker and director of the Center for Children of Divorce in the District -- feel that tying an allowance to chores is appropriate, as long as the expectations are clear.

"Be very specific," says Long. "Make sure the kid knows exactly what he should do to get his money. Give him a list of chores." And once you set up your system, follow through.

Weingartner started to give her children an allowance when they were 8 and 10 to teach them "the value of money. But it didn't work. Half the time I forgot to give it to them, and half the time they forgot to ask."

But after years of different systems and sometimes no system, Weingartner, her husband and their sons settled on only one rule: you get your $5 if your room is clean on Friday. "That seems to work. Sometimes they choose to get their money and sometimes they don't."

Other systems are more complex. Donna Blank, a teacher of Feldenkrais, a process of learning more optimal patterns of body movement, gives her daughter a dollar weekly no matter what, but 9-year-old Jessica earns points for performing such clearly delineated tasks as being on time or making her bed. These points gain her privileges such as television time and more money.

Blank praises the system for its effectiveness and clarity.

"This system developed out of finding that negative reinforcement didn't work. I learned to be very specific about what I wanted. This works," says Blank.

*The allowance as a reward.

Some parents misuse allowances by paying children for preferred behavior such as good grades or polite manners. Children, like adults, need recognition.

Says Simpkinson: "If money is the only way you recognize and validate children, then they will go through life just working for that. Some people will be glad for that because their kids will grow up to be rich doctors, but most parents do not want kids to be driven that way."

One mother of a teen-ager regrets using money to reward her rebellious 12-year-old for not causing fights on the school bus or tripping his classmates. "While it solved the immediate problem," she says, "it created another. Now that he's 15, I seem to be paying him for not teasing his sister or shouting at the housekeeper. Things have gotten out of hand."

*The allowance as a means of punishment.

Withholding money for infractions of other rules is another way parents mishandle allowances. The punishment, experts advise, should fit the crime; leave the allowance alone.

"If a child doesn't meet responsibilities," says Simpkinson, "do not cut the allowance. Take away privileges like TV, or have the child do extra chores. Avoid using money as the measure of all things in a family."

Warns Weinstein: "Tying money to behavior creates the impression that the child can buy your approval. An angry parent docking allowance in punishment . . . is, in effect, denying love, thereby getting love and money all mixed up in the child's mind."

*The allowance as a means of control.

"An allowance helps the child separate from the parents," says Long. "But with teen-agers, parents are most fearful of this very separation. So allowance is one of the illustrations of that struggle . . . Sometimes allowance is used inappropriately as an attempt to control."

Don't withhold allowance for vague "uncooperative" behavior, says Long; only dock allowance if the child violates the specific contract he or she negotiated.

"You want to teach them that you do not wield control over their allowance -- they do," says Long. "It's very wrong for parents of teens to use allowance as a weapon. It's manipulative and it creates resentment. Teens need money. If they do not have a job, and they do not get allowance, they may steal money or not eat lunch."

Sometimes parents wield control by excessively regulating a child's purchases. But "unless safety, ethics or family values are violated," advises Simpkinson, "let the child buy what he wants. That's his right."

Says Weingartner, "I wouldn't let Eric buy a TV or a phone for his room. Those are my values. But other than that, he can buy what he wants. It's his money."

Interfering with purchases, says Olivia Mellan, a District psychotherapist who often counsels individuals about money and emotions, "may give the child the unconscious message that he cannot be trusted with money, that he is greedy, and that his demands are outrageous."

Creating rules for purchases, particularly for teen-agers, says Long, "is a desperate attempt to hang onto the kid."

One more thing, advise the experts: Be careful how you hand the allowance to the child. Tone and body language count.

One woman remembers feeling confused and guilty on each allowance Sunday when her mother painfully reached into her purse to extract a $10 bill -- as if it were her last in the world.

Cautions Mellan, "If money is given in a rejecting way, if the parent always complains about the way chores were done, this would create self-doubt -- and resentment. But if the money is given fairly and without resentment, then the child can feel self-respecting, and this will create self-acceptance."