ONE DAY, while Miss Manners was tidying up, she came across an entire set of discarded manners. They had to do with second weddings, and Miss Manners had permitted them to fall into disuse when she noticed that second marriages were, as a rule, tending to be more sensible than first marriages.

Why, she reasoned, should first-timers be allowed to put so much money and valuable etiquette into creating memories they will try to forget, and experienced people be advised to be quick and inconspicuous about something they might like to remember? Thus, she abolished furtive second weddings, and set out fresh rules for festive ones.

But someone has to use those old rules. It would be a frightful waste to throw them away, and it is one of Miss Manners' principles that tradition should be preserved, even if it has to be taken to the dressmaker's and altered.

In her wisdom, she has made over the old second-wedding rules that they might apply to divorces. There seems to be a basic fairness in there, somewhere.

Here, then, are the new rules:

It is in bad taste to issue formal announcements of a first (or fourth) divorce. When you must notify people, do so by letter. This is also an excellent way of using up paper marked with obsolescent names.

No big parties are given, but some quiet celebrations may take place with relatives and intimate friends. The legal ceremony should be attended by as few people as possible, and later it might be desirable to share a drink. Parties afterwards, if one wants them, should be quiet and restrained (as opposed to boisterous and conspicuous).

Dress should be conservative -- suits for both ladies and gentlemen at their divorces, and conventional party clothes for the social events.

Children are naturally deeply involved in the occasion, both emotionally and logistically, but should not be present at any events. They should certainly not be in any formal supportive role. In private sessions, they are told what is about to happen, never asked or consulted as to whether it should (as nobody listens to their decisions, anyway, they should feel innocent of any responsibility); and they are kept entirely apart from the public part of it.

The couple should not expect presents, although those same close relatives and intimate friends may certainly choose to give presents. The basic principle is that one does not give household presents to people who may be presumed to have acquired the basics.

However, if this is, indeed, the occasion for a person's starting a fresh household from absolute scratch -- Miss Manners has heard that this is sometimes the case -- it is charming for friends to indicate their wishes for happiness in a tangible way. Strictly speaking, one does not hold showers in connection with such an event, but Miss Manners would be willing to look the other way if a close circle of friends were to organize a similar gathering privately.

You see, she really must insist on the proper tone. One may radiate quiet happiness, but that all-out triumphant air is not in good taste.

In compensation for this restraint, Miss Manners is, you remember, suspending the stricter rule for subsequent weddings. Thus, those who cannot wait for full-scale celebrating need only move to the next milestone. MISS MANNERS RESPONDS

Q. My husband's brother-in-law has a most vulgar habit. Whenever he comes over and thinks no one is watching him, he picks his nose and wipes it on the bottom of our table. I find it very disgusting for him to be using our tables as a tissue. Can you think of any remarks that are subtle, but effective?

A. The subtle way to deal with this is to give him a present of a box of fine handkerchiefs. The effective way is for you to tell your husband to tell his sister to tell her husband to stop being disgusting. Which do you want to be?

Q. Hi! I have a terrible problem. I like this guy and I've tried everything to get him to notice me. Then about a week ago, he told a friend of mine that I was getting too serious and I didn't even do anything to make him think that I was too serious. I need some help. I'm very depressed.

A. Hi! Don't be depressed. You have succeeded in making him notice you. Now see if you can make him notice that you are ignoring him.

Q. What is the proper way to eat onion soup that is topped with bread and melted cheese? It is usually difficult to cut the cheese with the soup spoon, and a small strand of cheese often strings along between the bowl and the spoon that is on its way to my mouth. Should I cut the cheese with my knife?

A. Miss Manners is sorry, but you may not eat soup with a knife, no matter how severe the provocation. Cut the cheese with the edges of your spoon, and watch out for your clothes. Then wind the trailing strand of cheese around your spoon before attempting to lift the spoon to your mouth. This is not really effective, but it can be a lot of fun.

Q. My problem concerns the proper way to greet the parents of a newly wedded bride or groom. I was aware that one congratulates the lucky groom and wishes the best of luck to the blushing bride. But what of the parents?

This question was raised in light of an occurrence at my cousin's wedding. In the receiving line after the ceremony, I was so filled with joy that I congratulated my aunt -- the mother of the bride -- on the wedding. She gave me a quite unpleasant look and replied, "Why congratulate me? It's not my wedding!" I was dumbfounded. I later regretted not having a snappy comment to save face (mine).

My dear Miss Manners, was I incorrect? Or was my aunt oversensitive? I am anxiously awaiting your reply, as I am soon to go to another wedding and wish to avoid such unpleasantness in the future.

A. Please convey Miss Manner's congratulations to your aunt. They are not offered on her daughter's wedding -- indeed, the rule about wishing the bride happiness, rather than offering her congratulations, applies to her family as well -- but because she has succeeded in creating an emotional disturbance on a happy occasion and suggesting that she is not satisfied with the match her daughter made. Anyone can marry off a daughter, but a mother who manages these feats in the brief time of a receiving line, is to be congratulated.

Q. When I call my friend Mrs. Goodtaste, and inquire if she is at home, it would be pleasing if daughter Nola or son Midas would utter something in addition to a curt "no," followed by complete silence.

Some alternatives might include 1) "Mumsy is out just now, but she will be home around five, would you care to call her then?"; 2) "Mother is unable to come to the phone just now, may she return your call?"; 3) "Dear Ma-Ma will be so dreadfully sorry to have missed your call, may I take a message?"

Having known these children since infancy, driven them to Scout meetings, entertained them and remembered all their special days, perhaps they might add something like: 1) "I do hope that you and Mr. Friendly have been well"; 2) "It is nice to hear from you"; 3) "We all hope you'll come by and see us when you can."

Of course, we have to face the fact that many of their parents aren't much better.

A. Do we have to? You are quite right, both in the problem you identify and the desirability of the sample dialogue you propose, but Miss Manners is not ready to concede that the ability to be courteous has been bred out of the human race, or perhaps has died out for lack of use.

This is another instance of the need to teach children hypocrisy. You and their parents know that they don't care whether you are well or visible because they took all your kindnesses as no more than their due. If they were forced to repeat these pleasantries by rote, however, one day they might listen to the words and wonder whether you and Mr. Friendly are not as human as themselves and as in need of kindness.