Q: I have a thick marble table that has many scratches on the top. Is there any way of getting rid of these scratches by sanding, or by some other method?

A: Scratches in marble have to be carefully polished out with fine abrasive putty paste -- a powder that is mixed with water. If the scratches are not deep you may be able to do it yourself with some of this putty powder, which you can buy from a marble dealer. But if there are many scratches and they are deep, I think this is a job for a professional with the equipment to do the job properly.

Q: I have a ceiling fan that vents into the attic. When the attic was insulated recently, the contractor extended the tube around the fan so it sticks up above the insulation. My problem is that the damper at the end of this tube does not open more than a couple of inches when the fan is on; (this condition apparently existed before the tube was extended, but we didn't know about it.) I don't want it open all the time because then we lose heat. Is there a solution to my problem?

A: The damper on your exhaust fan is not working properly because it is in the wrong position. They are made to be installed vertically -- that is, with the duct (what you call the tube) horizontal and aiming out through a wall, not straight up. Then the damper hangs or pivots by its own weight and gets blown open by the fan when it comes on. You could correct this by putting an elbow at the top, then adding a short horizontal length before you install the damper -- but you have a more serious problem.

Your exhaust fan should go directly outside, not into the attic. Grease accumulating in the attic could create a serious fire hazard.

Q: The attic in my house is finished, with two bedrooms and a bath. The door from each room opens into the crawl space behind the walls. Where the sloping roof meets the floor there were originally openings through which I could see daylight. We had to board these up from the inside because squirrels were getting into the attic.

Having read frequently in your column about the need for attic ventilation, I am now wondering, if we should do something about the lack of it. How can we solve this problem without letting the squirrels back in?

A: You can install mesh-covered vents or louvers that will let air circulate, but will keep birds, rodents and insects out. Various types are available at lumberyards and building supply outlets, and they are easily installed from the outside by cutting the right size opening, then pushing them in from below.

Q: Some of the rooms in my house had wallpaper on the ceilings and walls, and during the past 20 years these papered surfaces were painted over about five or six times. Now some of the paper is beginning to crumble, especially on the living room ceiling. Is there any way of removing this painted-over paper without damaging the plaster underneath?

A: With that many layers of paint over the paper it will be a job -- but it can be done. I would rent or borrow a belt sander. Try to get one that is not too heavy, because you will have to hold it overhead. Buy the coarsest-grit sanding belt you can find, then use the machine to scratch or roughen the paint.

You don't have to get it all off, just scratch through it so that when you use a wallpaper steamer, the steam will penetrate through the paint to soften the paper and paste underneath. Wear goggles to protect your eyes, and a face mask to protect against dust.

Another machine you can try is a very coarse, wire-type rotary paint stripper. Again, the idea is to scratch the surface thoroughly. In either case, after this, rent a wallpaper steamer from your local paint dealer or tool rental agency, and use it to get the paper off. Buy a special knife or scraper designed for getting paper off the wall; sometimes these will work (without steaming) if the paper is already starting to let go.