Q: There were originally small cork disks under a sheet of heavy glass that covered the top of our mahogany coffee table. The disks left marks on the surface of the table. We tried rubbing with paste wax, but this did not get them off. Is there any simple way you can suggest for removing them?

A: I suggest that you first rub the marks with one of the toothpastes advertised as having extra whiteners -- these actually have a very mild abrasive in them. If this doesn't do the trick, try a paste made by mixing powdered rottenstone or jeweler's rouge (sold in paint stores or hobby shops) with a little salad oil. This should take the spots out if they are not too deeply embedded. The surface will then be dull, but the gloss can be restored with wax or polish.

Q: When my apartment was painted, the painters smeared paint all over the electrical wires that supply my radio and stereo. What kind of solvent can I use to remove these unsightly smears without damaging the insulation on the wires, and without danger of getting electrocuted?

A: Depending on the kind of insulation your wire has, chances are you can remove the paint smears by wiping with lacquer thinner or nail polish remover. First, unplug the wires from the wall, then try the thinner on a small section of the wire. If it doesn't soften the covering, you can go ahead safely. Just remember that this solvent is highly inflammable, so make sure there is plenty of ventilation and keep flames away until the solvent has evaporated. You can safely plug in again after the wire is completely dry; (a few minutes at most).

Q: I have a six-foot-long pine window sill. My husband finished this by sanding it to the bare wood and applying a stain and three coats of spar varnish. However, for some time now about two feet of this sill is bubbly and the varnish is sticky. I don't understand why this is happening to just one spot. How can I remove the varnish and seal the wood so this won't happen again?

A: You do not make it clear whether the bubbly and sticky condition was present from the beginning or developed later. There may have been something in or on the wood in that area that prevented it from drying properly. Something may have been spilled on the surface to cause the problem. Whatever the cause, you will have to scrape or sand the varnish off -- at least in that area. But unless you do the whole sill, the one section will probably look different.

Sand the surface until it is of uniform color and no sticky or bubbly surface remains, then wipe with a rag moistened in paint thinner. Allow to dry, then re-varnish with urethane-rather than spar.

Q: I would like to tone down the noise that filters into my apartment from the buses and other traffic on the street below. What can I use to insulate my windows, or do I have to install double windows?

A: Foam boards can be fitted into the inside of the window frame to cut down on noise, but this will, of course, also cut out light if you leave them up during the day.

You can build shutters with plywood or paneling on the inner side (where you can see it) and foam board on the outer side where it fits against the frame. These can be removable or hinged so they can be opened during the day.

You can also put up do-it-yourself plastic storm windows on the inside. These will let in all the light you had before, cut down on sound transmission and save on heat during cold weather.

Q: We have a 46-year-old house with a brick exterior and slate roof. There is no insulation in the attic or walls. We have been advised to blow insulation into the walls, as well as over the attic floor, but others have told us that with brick walls insulating the outer walls is not really worthwhile. Who is right?

A: You should definitely try to insulate your walls as well as your attic floor; (if you plan to finish the attic later, apply the insulation up against the roof rafters instead.) Brick is actually not a very good insulator, so don't minimize the need for having regular insulation blown or pumped into the wall cavities.