Q. For 45 years I have been looking for a good marble cleaner, unsuccessfully. I have a marble fireplace and marble table tops. The tops are a particular problem, as they have acquired glass ring stains that I am unable to get off. Can you help?

The fireplace sounds like pretty old marble, which is all white, so you can wash it with detergent and water, with a quarter cup of bleach added. For the table top marble, washing with detergent and water will at least make it clean. And for those pesky ring stains, rub with Mr. Clean Magic Eraser.

Whole lot of shaking going on

Q. I live on the third floor of a triple-decker and when I do my laundry the floors shake during the spin cycle. The house was built in 1890 and the floors are original. The planks are nailed in and have been refinished a few times so they are very soft. The floors also shake when walking through the unit, so I know it is not an issue with an unbalanced washer. If I were to replace the subflooring, screw it into the joists real tight, and maybe even sister a few of them up, would it help ?

Putting a thick pad under the washer might help, but don’t count on it. I think the floors shake because the joists, those horizontal beams holding the floor up, are not large enough (2-by-8 or so instead of 2-by-10 or 2-by-12), and/or span too long a space. This is aggravated by the fact that the house is balloon framed. That means studs and other vertical pieces go from foundation to attic, with all horizontal pieces (joists, for instance) hung on those vertical studs. That makes components of the structure virtually one piece, so that if one part shakes, they all do. Any movement, such as walking or spinning the washer, will cause the shaking.

Reinforcing the floor or subfloor under it is unlikely to work. The joists need to have heavier, deeper joists installed beside them. If you own the house, have a renovation contractor or renovation architect take a look and suggest a cure. If you don’t own, your landlord might do it. It would be a major project.

Removing stains on stone

Q. We installed bluestones at the entrance (a wide landing, 4 by 10 feet) to a house. Leaves stained them. We tried removing the stain with hot/cold water and brushing it with various soaps/detergents. When these did not help, we used various cleaners and acid. Unfortunately the stains were not removed and it looks bad. It is the first thing you see when you enter the house, which the owner spent a fortune to remodel.

If the acid you used was muriatic acid, it should have worked. If it was not, you could try using muriatic acid. Buy it in a hardware or paint store. Mix half and half with water (always pour the acid into the water), and pour or brush it on the stains; after the fizzing stops, brush with a scrub brush and rinse. If that does not work, apply full strength household bleach, wait a few minutes, and rinse. Always wear skin and eye protection when working with bleach or acid, and be very careful. A final try: sand the stains with fine sandpaper.