Q I have several white shirts that have yellowed over time, including a few that were laundered some time ago and not worn since. Is bleaching the only way to remove the yellowing? What about the shirts with white collars, but colors elsewhere, making bleach a nonoption? I hate to simply throw away the shirts.

A Oil or perspiration can stain white shirts, leaving them or gray or yellow. But don't throw them away yet. Try removing the stains:

• Pour liquid detergent such as Wisk directly on collars. Rub it into the stain, but not too vigorously. Let set for several minutes and then launder in the hottest water that's safe for your shirt. Or use a stain pretreatment such as Shout or Spray 'N Wash. Some people claim to have had success treating the collars with shampoo.

• Or, apply ammonia to fresh stains and white vinegar to old stains. Rinse with water before washing.

• Even on shirts with color, you can use a bleach (either chlorine or color-safe), unless the shirt label warns against any type of bleach.

• If the stain does not come out, soak the shirt in suds of soap or detergent and water for a few hours or overnight. Some have found that a solution of automatic dishwashing detergent and water works on white shirts. (Be sure to test on a less valuable shirt first.)

Remember to treat stains as soon as possible. Perspiration may weaken textile fibers if allowed to remain on the fabric. Ironing may permanently set a stain. It's a good idea to follow these steps each time you launder the shirts, to prevent soil buildup.

Includes information from University of Minnesota Extension

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.