Dear Pat: I try to keep the bathroom as clean as possible, but the caulk around the bathtub and shower stall is black. Can you tell me how to clean the caulk or, if necessary, how to replace it? — Diane H.

Dear Diane: No matter how clean you keep your bathroom and bathtub, they will never look really clean if your caulk is discolored or black. What's worse, there is no sure way to clean caulk and make it white or clear again once it has become discolored.

But, hey, miracles happen. It won't hurt to try cleaning your bathroom caulk first. You could be lucky and get it light enough that it looks acceptable, but don't get your hopes up.

That dark color is caused by a stubborn combination of dirt and mildew. You can first try experimenting with a standard bathtub cleaner to get rid of those nasty stains.

If bathroom cleaners fail to do the job, you can also use a solution of 1 part bleach and 4 parts water. The bleach in the solution will kill the mildew and could bleach out the stains somewhat.

If after cleaning and bleaching you are still dissatisfied with its appearance, your only remaining option is to replace the old caulk. This is not a difficult do-it-yourself job and should only require one $5 tube of caulk.

The first thing you need to do is to determine the type of caulk already in place in your bathroom because knowing that will determine how much removal is required.

The caulk at the joint where the top of your bathtub meets the wall serves two purposes. First, it creates a seal to keep water from getting under the wall tile. Second, it creates an attractive joint.

If your existing caulk is dry and brittle, it is most likely a latex caulk. This type of caulk will have to be completely removed because it will be cracked and unable to provide a good water seal. Latex is an inexpensive type of caulk that was commonly used by builders years ago. Saturating latex caulk with 90 percent isopropyl alcohol will make it easier to remove.

If the caulk seems rubbery, it is likely a silicone caulk. This caulk has a very long life. Even though it is discolored by mildew, it is probably still providing a good water seal.

In this case, you only need to remove a top skin of the caulk, or perhaps none at all. Just a new thin layer of white silicone caulk could do the trick.

For a few dollars, you can purchase special plastic caulk-removing tools at your local hardware store. These are designed specifically for bathtubs because bathroom caulk is replaced often, but the tools will work for kitchens and around windows, too.

These tools are most effective on crumbly, old latex caulk. Warning: It might take a bit of elbow grease to remove bathroom caulk.

Make sure to use kitchen and bathroom caulk. These are formulated with mildew-resistant chemicals that are quite effective.

The following companies make these caulks: DAP, 800-543-3840; Elmer's Products, 800-848-9400; Geocel, 800-348-7615; Macklanburg-Duncan, 800-654-8454; and Red Devil, 800-423-3845.

Here are some tips to reduce future mildew growth:

— When you are done bathing, rinse off the walls and caulk of the bathtub and shower enclosure with water to minimize soap residues.

— Open the shower door or curtain after bathing so your tub and shower will dry faster.

— Run the bathroom vent fan for several minutes after showering.

— Once a week, wipe the caulk in the bathtub and shower enclosure with a mild solution of bleach and water to retard the initial mildew growth.

REQUIRED TOOLS AND MATERIALS

— Scraper

— Utility knife

— Caulk

— Caulking gun

— Bucket

— Rags,

Send your questions to Here's How, 6906 Royalgreen Dr., Cincinnati, OH 45244 or visit www.dulley.com. To find out more about Pat Logan and read features by other Creators Syndicate writers and cartoonists, visit the Creators Syndicate website at www.creators.com.

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