DEAR MR. MELTZER: My husband bought a house before we were married. He made his mother the beneficiary in the event something happened to him.

We both have wills leaving everything to each other. If something happened to him, would the house be mine and the kids', or would it be his mother's?

If his mother dies, does that eliminate the beneficiary claim? The house is in his name only.

ANSWER: From your letter, it would seem as though your husband had signed the will prior to your marriage, leaving the property to his mother.If the new will (which both of you have signed) was prepared after your marriage, this would be the document that would be valid today.

Therefore, if the new will leaves you the property, then him mother no longer has a beneficiary interest. The most recent will is always the valid one before the courts, unless it was prepared under unusual circumstances.

However, from a tax standpoint, it would be better if you and your husband owned the house as tenants by the entireties. In this way, the house would automatically be yours if your husband were to die, and you would avoid paying estate taxes.

DEAR MR. MELTZER: One of our kitchen appliances was badly in need of oiling. I used machine oil, which did the lubricating job, but it left a bad tast on the food.

My wife says there must be a way of oiling appliances without that problem popping up. After all, other people must have to lubricate mixers, beaters, can openers, etc.

ANSWER: Use cooking oil. It will do just as good as job as machine oil and you'll find that it's tasteless.

DEAR MR. MELTZER: It has come to my knowledge that builders, as well as lending institutions, are reluctant to sell houses or to approve mortgage loans to those who have no intention of using property but will keep them it investment purposes.

If that is so, how could people purchase their second houses without being turnd down?

ANSWER: There has been a traditional approach in the lending market to favor owner-occupied properties. It is obvious that a house that is lived in by the owner will be treated better than one occupied by a tenant.

Many savings and loan institutions will not lend mortgage money for investment purposes.

A second home generally means that the owner intends to occupy it for at least some part of the year. Usually, such homes are subject to seasonal markets and are only occupied in the summer or winter. As long as the owner does live in it for part of the year, banks seem to be willing to provide mortgage money, assuming the owner has sufficient income to pay for two houses.

DEAR MR. MELTZER: I'm an antique buff. I have been "picking up" little and big pieces for years,but find I have a problem with the many pieces of copper I now own. Cleaning them has gotten to be a terrible chore.

Do you know of an easier way to clean copper than the hard rubbing I am forced to do now.

ANSWER: Dip a wedge of lemon in salt and rub it over your copper pieces. You'll be surprised and pleased with the results.

DEAR MR. MELTZER: My wife inherited some beautiful paintings recently but we don't know how to take care of them. Should they be dusted, and with what?

ANSWER: Valuable art objects should be handled with care. You may, of course, dust them. But beyond that I would be very careful.

Great damage can be done to paintings by using the wrong cleaning methods. It really should be done by an expert. By contacting your local art museum, you can be guided to where to go to have them cleaned and repaired, if necessary.

Bernard C. Meltzer is a realtor, engineer and appraiser. He does not answer letters personally but only through his column. Address: Suite 900, 112 S. 16th St., Philadelphia, Pa. 19102.