Make your home sparkle from top to bottom with helpful cleaning tips from Martha.

Damp, dirty sponges harbor and transmit germs that can spread food-borne illnesses. Recently, researchers set out to find the most effective way to sanitize this common kitchen item. The results: a virtual tie between microwaving a damp sponge for one minute and cleaning it in the dishwasher with the drying cycle on. In both cases, 99.9 percent more bacteria were eliminated than with other methods tested. Use the microwave or dishwasher technique every other day (wet sponge before microwaving to decrease risk of fire). Wring sponges out after each use, and store them where they can dry thoroughly. Designate different sponges for specific tasks to prevent contamination. Replace frequently used sponges every two weeks.

This residue, called scale, is a harmless buildup of minerals -- primarily calcium and magnesium, found in hard water. To remove the deposits inside your tea kettle, boil equal parts white vinegar and water. Turn off the heat, and let the kettle sit for a few hours. Rinse and repeat as needed until the interior is clean. Drip coffeemakers also need routine cleaning. Once a month, fill the reservoir with equal parts white vinegar and water, and turn on the coffeemaker. Halfway through the cycle, turn it off. Let it sit for an hour, and then let the cycle finish. Afterward, run a few cycles with just water to rinse.

Although they're probably immersed in suds daily, bath toys need tub time of their own to keep clean. Soak toys for 10 minutes in one part hot water, one part distilled white vinegar, and a few drops of dishwashing liquid; use a utility brush or old toothbrush to scrub crevices. Let moldy toys sit in a solution of 3/4 cup chlorine bleach per gallon of water, following directions on the bottle's label. (Chlorine bleach should never be mixed with any other household cleaner, since harmful fumes can result.) If squeeze toys are harboring black sludge, discard rather than try to clean them. After washing, rinse toys well in warm water and let dry before putting away. After each bath, shake excess water off toys and empty squeeze toys completely; store in a well-ventilated area.

To lift the offending smell from a wooden board, scrub the surface with coarse salt and lemon juice or with a baking soda paste. Rinse, and wipe dry. Clean a plastic board with hot, soapy water or, if it fits, in the dishwasher. If the smell lingers, wash it again. As a last resort, add a teaspoon of bleach to a quart of water, and apply to the board's surface. After a few minutes, rinse well and dry.

Chocolate stains are a mix of oily, waxy substances and pigment, which means they're best tackled in stages. If there is a lot of chocolate, freeze it first: Put ice cubes in a resealable plastic bag, and place it on the chocolate. Once the chocolate hardens, gently scrape off as much as you can with the top edge of a dinner knife blade. If there's just a little, brush away what you can with a clean, dry toothbrush. For machine-washable materials, dab stain remover or undiluted liquid laundry detergent and wash in the hottest water the fabric tolerates. For upholstery, blot using a cloth dampened with hot water and dishwashing detergent. Adjust the cloth between blots so a clean portion touches the material each time.

In order to be effective in the hot sun and in water, sunscreens contain moisture-repelling substances and waxy compounds. It's generally these ingredients that make removing such stains a challenge. To eliminate the smudges from leather, blot with a clean, dry cloth. Then blot with a cloth barely dampened with hot water and a few drops of dishwashing liquid, continuing until mark is gone. Follow up with a cloth dampened with water to remove any traces of detergent.

Before the invention of stainless steel, cutlery had carbon-steel blades. While these are especially sharp, the surface is quick to oxidize, becoming dark and dull when it touches oily or acidic foods. Brighten your knives' blades by polishing them with fine steel wool and Noxon metal polish. To prevent rust, wash the knives after each use and dry them immediately. Then, with a cloth or paper towel, wipe a thin layer of mineral oil onto the blade to protect the steel from corrosion. Finally, store them in a location with low humidity. If your knives are rusted, stained, or scratched, have them professionally buffed.

Outdoor showers are usually constructed of low-maintenance materials, such as cedar or a composite polyvinyl chloride (PVC) material. If the structure is well ventilated and can dry thoroughly between uses, it shouldn't require much upkeep. Sometimes green algae will grow on PVC. To remove it, use a soft-bristle brush and a weak chlorine bleach solution, followed by a good hosing down. Wood is less likely to attract algae but may develop a dark film that can be removed with a pressure-washer. Spritz wood periodically with a weak bleach solution to kill any bacteria or mold. A note about plumbing fixtures: Sea air will erode some metals (like chrome and brass). Accept the rugged look, or choose stainless steel or nickel; these hold up better in salt air.

The best way to keep pots spot-free depends on the material. Stainless steel can be polished using a soft cloth and white vinegar or lemon juice. (Don't soak the pots because the surface can pit.) When you wash the pots, dry them with a towel; don't set them out to air dry. To remove dark spots from aluminum, rub a nylon pad along the grain of the metal as it's drying. If that doesn't work, mix two tablespoons of cream of tartar and a quart of water in the pot, and simmer for 10 to 15 minutes. Empty the pot. When it's cool, scour with the nylon pad, or use a cloth and mild cleanser.

Latex-based paint isn't usually a disaster for hardwood flooring, even if the spill has gone untended. You can probably remove it with rubbing alcohol. Apply the alcohol to a clean, white cloth, and test it on a hidden area of the floor to make sure the finish won't be harmed. Then rub the spill. If more friction is needed, switch to a soft-bristle brush or plastic scraper. If rubbing alcohol doesn't work, try a product designed to clean dried latex paint, such as Goof Off (available at hardware stores). Be sure to read the instructions and test the product on a small inconspicuous area. Use it sparingly, following the method described above, until all traces of paint are removed.