Dear Ken: I have a disposer with a strong moldy smell I can’t get out. Any suggestions? — Joanne

Answer: Grab an old toothbrush, dip it in full-strength ammonia and scrub the underside of that rubber splash guard and as much of the inside top of the disposer shell as you can. For a more thorough cleaning, use a dedicated round toilet-bowl brush for this task. Insert it into the hole to scrub those same undersides. When you remove it, cover it with an old bath towel to prevent splatter.

About once a week, throw a handful of ice cubes and a half lemon into the disposer and run it with plenty of water for a few minutes. Also, I like to dump about a cup of pine oil cleaner into my disposer once in a while just before retiring for the night. The scent works its way under and around the blades and into the outlet holes.

Dear Ken: What’s the product you mentioned to use after regrouting my tile? — John

Answer: Once the new grout has cured for a week or so, you can apply some liquid sealer. This is usually a silicone-based product that discourages staining and scum buildup. It’s an optional treatment in the bath, but it’s vital to use it on kitchen floors and countertops, where food or liquid stains are likely to get into the grout lines and discolor them. This material tends to wear away and fade in strength over time, so test it occasionally to see if it still beads water droplets. Count on renewing it once or twice a year.

Dear Ken: I live in a two-story house that was once a summer home only. The heat consists of a wall furnace and several wall mounted electric heaters. I also have a fireplace. Is there some single heater that would be better than all this? — Ellie

Answer: Your through-the-wall heater is OK if it’s modern enough to have a sealed combustion chamber — that is, it draws its fresh air directly from the outside. Have it checked for safety and cleaned each fall by a heating contractor.

Why not consider a fireplace insert? It’s a sort of gas log with an attitude. That is, it doesn’t waste heat the way a simple decorative log set would. It’s essentially a gas furnace sitting in the fireplace opening. They’re available in ratings up to about 40,000 BTUs — which, granted, is only about 40 percent of a normal central-heating furnace. But that’s all you may need, since you’ll still get supplemental heat from your wall furnace. Once it’s installed, you’ll almost certainly be able to get along without firing up those expensive electric heaters.

Dear Ken: I work on refrigerated trailers. We’re always warned that the urethane foam is flammable and produces toxic fumes when it burns. So why is the canned foam good for home insulation? — Brian

Answer: It’s never a good idea to leave insulation exposed in the living area. Canned foam has a polyurethane base, which can char and smolder when it burns. That produces toxic fumes, like carbon monoxide and dangerous hydrocarbons. So it’s vital to cover any inside applications with some sort of fire-resistant skin, such as sheetrock. The same goes for batt insulation with a flammable paper facing. This material has a tar-like base that also can smolder and produce fumes, so you’ll see a warning label instructing the installer to cover it so it’s not exposed to the indoor living space.

Fiberglass insulation, although not flammable, can be a breathing hazard. Uncovered, it can release tiny particles of the spun glass into the air. So if you have an unfinished basement where the kids hang out, cover all the exposed insulation edges and ends with heavy plastic to encapsulate them. Bottom line: Insulation, no matter what kind, is safest when it’s covered.

Moon is a home inspector in the Pikes Peak region. His radio show airs at 9 a.m. Saturdays on KRDO, FM 105.5 and AM 1240. Visitaroundthehouse.com