Home should be a safe, happy haven from the world. Learn how to keep every part of your family's space healthy and hazard-free with environmentally friendly advice from Martha.

No. 5 containers, which are made of polypropylene, include yogurt cups, margarine tubs, drinking straws, takeout containers, and some water filters. More municipalities are recycling this plastic, but most still collect only No. 1 (soda and water bottles) and No. 2 (milk jugs) plastic. You can take your clean No. 5 containers to some Whole Foods stores. (Find a location near you.) The company Preserve uses the plastic collected at these drop-off points to make household products such as toothbrushes and mixing bowls. If there isn't a location nearby, mail your No. 5 plastics to Preserve. (The company analyzed the environmental impact of recycling through the mail and found that the benefits outweigh any harm.)

To keep bedbugs out, control what comes in. Avoid secondhand furniture: Bedbugs love to nest in folds of upholstered pieces, but they also inhabit fabric-free items like dressers. In hotels, inspect the bed, paying particular attention to crevices, as soon as you arrive. Store bags on luggage racks, and keep them closed when not in use. When you leave, check your belongings for unwelcome stowaways. At home, cut clutter, move furnishings away from walls, and check mattresses and pillows from time to time. If bed bugs do find their way in, call a licensed exterminator who specializes in integrated pest management -- an environmentally sensitive approach that manages pest damage with the least possible hazard to people and property.

The most natural way to deal with little black ants is to make your home inhospitable to them. Keep food stored in airtight containers, and be vigilant about cleaning up dishes and crumbs and taking out the trash. Block possible pest entryways by caulking crevices along baseboards, around cabinets and pipes, and outside around the foundation of your house. 

Boric acid powder, sprinkled into exterior crevices or mixed with sugar or syrup as bait, can be an effective poison. Though less toxic than conventional poisons, it's not completely safe and shouldn't be used near kids and pets. Diatomaceous earth is a safer choice. To use either, find the location where the ants are nesting, and surround the area with the powder. If the problem persists, find an integrated pest-management specialist.

When heating systems are running continuously, the air dries out and humidity levels drop, which can lead to parched throats, itchy eyes, and respiratory problems. A humidifier helps keeps the humidity at a comfortable level, usually 30 to 50 percent. Cleaning the humidifier regularly is a must, as mildew and mold can grow in just a few days. Change the water daily, using distilled or demineralized water to reduce buildup. After emptying the tank, dry it completely. Clean the various parts a couple of times a week, following the manufacturer's guidelines. In general, use a vinegar-water solution and disinfect with diluted bleach. After cleaning, rinse thoroughly and refill with water.

Almost any new computer will be outdone by the next generation of processors and hard drives in a matter of months. What is now a state-of-the-art machine might seem like a dinosaur in a few years. Think about those who might still find it useful: Local schools, training institutions, or nonprofit organizations are a few places to start. If your computer is too old to be of use, it may indeed be ready for the trash. But don't simply throw it away: Computers contain poisonous materials such as lead; many states classify them as hazardous waste. As a rule, they should be disposed of just like other household appliances. Depending on where you live, that could mean leaving it on the curb for bulky waste collection or taking it to a recycling center; call your local environmental protection agency for details on the rules in your area.

Given all the power-hungry machines in a house, many people assume that the choice of one light bulb over another has only a tiny effect on overall consumption. However, many light bulbs get used every day and night throughout the house, accounting for as much as 25 percent of a household electricity bill. Energy-saving bulbs -- compact fluorescent bulbs (CFLs) that screw into standard incandescent bulb fixtures -- can make a difference. Opting for a CFL results in a whopping 75 percent reduction in power consumption versus that of an incandescent bulb. Multiply the savings by the number of homes on your block, in your town, and in your state, and the drain on resources and power grids decreases dramatically. However, CFLs contain mercury and will need to be recycled; visit lamprecycle.org for local laws and drop-off locations.