A reader wants to know how to remove this pink stain that formed between shower tiles. (Reader photo)

Q: I recently completed a house renovation that included installing white subway tile with white grout in the shower. Now, the grout has turned pink. I’ve tried using nontoxic cleaners, a toothbrush and some elbow grease, to no avail. How can I remove this unsightly staining?

Washington

A: What you’re seeing is often called “pink mold.” It is actually a type of bacteria, Serratia marcescens.

Bubbly liquids often dislodge this growth, even when scrubbing does not. Try dribbling club soda along the top edge of the tile, or at least above the area where the grout is pink. Then quickly follow with an old toothbrush to distribute the soda along the grout lines. Pour on more soda as needed so all of the grout gets wet. Wait a few minutes, and the pink color is likely to disappear.

If it persists, repeat this procedure but use hydrogen peroxide, in the 3 percent concentration sold in brown plastic bottles at drug and grocery stores. Chlorine bleach also works, but it stinks up your bathroom and bleaches your clothes if any spatters on you.

A reader wants to fix this broken glass decanter. (Reader photo)

The organism you’re dealing with can be deadly in certain circumstances, according to a Scientific American article published in November 2011 and available online. The article, “Miraculous Microbes: They Make Holy Statues ‘Bleed’ — and Can Be Deadly, Too,” reported that it’s a top cause of certain hospital infections and was implicated in at least one death when it was sprayed over San Francisco Bay in the 1950s in a test of how bioweapons might disperse. (The bacteria was used because its color made it possible to detect how it spread.)

But on grout and shower curtains, pink mold is really just a cosmetic issue. The bacteria grow on surfaces that stay damp for long periods, especially where there is also soap scum. So to help prevent regrowth, wipe down shower walls with a towel or well-wrung-out sponge after the last person has showered each day. A squeegee isn’t so effective. Although it wipes moisture from the tiles, it leaves grout lines damp because they are recessed.

Q: I recently broke an old clear-glass decanter. I don’t expect that it could be made to look as good as new and would be satisfied if it could be made to look intact from a few feet away. I would never use it again to hold any liquids. Is there any place that could repair it?

Luray, Va.

A: Giovanni Nason Glass and Crystal Restoration Center in Potomac (301-340-2624; gnason@comcast.net) does this sort of repair. But the owner, Giovanni Nason, warns that it’s probably not worth the cost unless this piece has high sentimental value to you.

“The piece is a disaster,” Nason said after looking at the picture you sent. “It can be put together, but I don’t think it’s going to be a great job.”

He estimated that he would need to charge about $400 to glue the pieces back together, using a professional-grade epoxy that wouldn’t yellow over time. That price would also include spraying the piece with a finish that contains minute gold flakes, which would help disguise the seams.

He doubts that your decanter would be worth what the repair would cost, even if it hadn’t broken. “It is not a Baccarat,” he said, referring to a company in Baccarat, France, that makes crystal glassware, including decanters that often sell for more than $1,000.

But value is something you need to decide. “If it was given to her by a great-grandmother who came to America on the Mayflower, it might be a different story,” Nason said.