White clothing is notoriously difficult to keep clean, so the crisp white blazer, blouse, or jeans you’ve been sporting since Memorial Day may look dingy all these weeks later.

Resist the urge to bleach them, the duo behind the Laundress collection of detergents and fabric-care products, Lindsey Wieber and Gwen Whiting, said. “Bleach often causes more ‘yellowing’ than whitening, especially with nylon and spandex,'” the aptly named Ms. Whiting said. “Bleach also weakens the fabric so it won’t last as long.”

Visitors to their Web site, www.thelaundress.com, can direct laundry-related quandaries to Ms. Wieber or Ms. Whiting. They say the most common question is how to remove yellow or gray underarm stains – caused by a mixture of deodorant ingredients, body oils, and fabric absorption. Their recipe, for cottons or cotton blends: Pre-treat the item with a stain remover, place in boiling water, let soak until water cools to room temperature, and repeat if necessary.

Dousing a fresh stain with water will only spread it or set it, Ms. Wieber said. “It will be easier to remove if you just let it be,” she said.

Some, of course, will insist on combating stains the old-fashioned way – with a washing machine. And having washed white cloths stained with coffee, grass, chocolate syrup, mud, and other liquids, Consumer Reports magazine reported last year that Tide With Bleach was the best stain-fighting commercial detergent on the market.