Q I have some Playskool blocks that are at least 40 years old. They are in good condition but they are painted. Are they safe for a grandchild to play with now?

A It depends. You could test the blocks for lead with an at-home swab test kit, said Justine Greene with the Minnesota Department of Health Lead Unit. But those tests aren't very reliable. A more reliable test could be done at a lab, but those tests usually involve destruction of the toy.

So your best bet might be to just put the blocks away until your grandchild is old enough to play with them without putting them in his or her mouth. Make sure children wash hands after playing with blocks, just as you would no matter what they are playing with.

Make sure the blocks are in good condition, that the paint is intact and there's no chipping.

For more information about lead, go to www.health.state.mn.us/lead.

Problem condensation

Q How do we stop condensation and ice from forming on our sliding glass doors?

A When warm, moist air in the home contacts the cool window glass, the vapor in the air turns to liquid and, when cold enough, to ice. To prevent or minimize condensation, lower the indoor humidity and raise the temperature of the window glass.

Some possible solutions:

• Keep window curtains and shades open at night so that air circulates and warms the glass.

• Operate the kitchen exhaust fan every time you cook, to eliminate moisture. Make sure the fan actually blows to the outdoors and doesn't just recirculate. Look in the cabinet above the fan. If you see ductwork, then the fan exhausts to the outdoors. If not, you have a recirculating fan, which does not eliminate moisture. In that case, you'll want to crack the window when cooking. (Some homes have downdraft exhaust fans with the vent housing under the cooktop.)

• Operate bathroom exhaust fans while bathing or showering and for 15 minutes afterward. You can increase ventilation in the home (bringing more fresh air into the home) by operating the kitchen or bathroom fan for a period of time every day, beyond when you're bathing and cooking.

• Do not vent the clothes dryer to the indoors.

• Use a hygrometer. (They're available at hardware and home stores.) The colder it is outdoors, the lower the humidity level should be indoors if you want to prevent condensation. Many Minnesota homes in winter can't handle humidity levels above 50 percent. But if the humidity is too low, it can lead to dry skin, bloody noses and shrinkage in wood floors and chairs. A compromise is best. Lower the humidity by increasing ventilation. If you have a little ribbon of condensation around the bottom of the windows, no problem. If you have to mop it up, it's too much. That can lead to mold and indicates that there could be larger problems in attic and wall cavities.

Send your questions to Fixit in care of the Star Tribune, 425 Portland Av. S., Minneapolis, MN 55488, or call 612-673-7032, or e-mail fixit@startribune.com. Past columns are available at www.startribune.com/fixit. Sorry, Fixit cannot supply individual replies. Fixit appears every day except Friday.