Dear Martha: What is a drop ceiling? Are there options for replacing one?

A: Drop ceilings consist of a metal grid that hangs from the ceiling joists and holds panels. They're often found in basements, because they allow for quick access to plumbing, wiring and other mechanical systems. If the drop ceiling is located elsewhere in the house, it was likely an inexpensive way to conceal a cracked or damaged plaster ceiling.

Although practical, drop ceilings aren't necessarily pretty. Fortunately, these ceilings are fairly easy to replace, but you'll be left with the original issue, be it exposed pipes or water stains.

If the drop ceiling was deployed to hide the house's systems, your best bet is to upgrade the panels. You might be able to take advantage of the existing grid system and simply swap in new panels.

But if the drop ceiling is covering damaged plaster, and if you want to reclaim a few inches of lost ceiling height, you can remove the panels and grid, and repair the plaster, or put up drywall over the plaster.

Dear Martha: How can I make fresh garlic last as long as possible?

A: First, purchase only loose garlic (not bags of garlic heads) so you can hand-select the healthiest ones. Fresh garlic should feel firm: Soft spots suggest the cloves have begun to spoil. In addition, look for heads with dry, papery skin. It should be snowy white, and not speckled or mottled, which indicates the onset of mold.

When you get home, store garlic in a mesh bag in a dark cabinet, or in a decorative pottery garlic keeper, which is nothing more than a lidded ceramic pot with small air holes. These conditions will keep the bulbs dry and dormant for up to two months. A brown paper bag, closed loosely and kept in a light-free place, is also an effective storage container.

The refrigerator's vegetable crisper, on the other hand, is moist and chilly, a combination of conditions that causes garlic to turn moldy and eventually sprout. Peeled garlic cloves can be stored in the freezer in an airtight bag or container for several months; once thawed, however, they will be softer than fresh cloves and their flavor will not be as intense.

Storing peeled cloves immersed in olive oil, this method is known to provide a breeding ground for botulinum bacteria and should not be used.

Dear Martha: What is the secret to removing tree sap from clothing?

A: As with any potential stain, it's important to treat sap while it's fresh. This will prevent the stain from setting and possibly causing permanent discoloration.

With delicate materials, such as silk or satin, dry cleaning is the best alternative. But with a more durable garment, such as a cotton shirt or denim jeans, you might consider a home remedy.

If the drip is fresh, try to soak up any sap with a paper towel. If the sap has started to harden, your best bet is to hasten the process by rubbing the area gently with ice (press the ice against the wrong side of the fabric to avoid forcing sap into the fibers). Then scrape away the hardened sap carefully with a dull knife. Dab the remaining sap with mineral spirits or oil solvent, and let it air-dry. Rub laundry detergent over the area to help break up the spirits or solvent, and wash the garment as you normally would. *

Questions should be addressed to Ask Martha, care of Letters Department, Martha Stewart Living, 11 W. 42nd Street, New York, N.Y. 10036. Questions may also be sent by electronic mail to: mslletters@marthastewart.com.