How to Clean Mildew from Shower Caulk

As an Amazon Associate we earn from qualifying purchases.

Caulk is a flexible sealing substance useful for filling the joints around window edges, shower edges, and others. As caulks get old, they develop Mildew or molds on them, which makes us wonder: how to clean mildew from shower caulk? Mildew is a generic reference to mold growth, and it needs immediate eradication, which is quite possible with household remedies.

How to Clean Mildew From Shower Caulk?

Delaying the removal of Mildew from shower caulk might accelerate the growth of mold. Hence, it might affect your health with allergies, eye irritation, and other such problems. Therefore, follow these steps and methods to learn how to clean Mildew from shower caulk.

Method 1: Cleaning Mildew Using Ammonia

Ammonia is an essential product that has proven its effectiveness in cleaning shower caulk.

Step 1: Prepare and Ventilate the Area

Ensure that there is proper ventilation in the cleaning area. It is because the presence of ammonia can cause adverse effects on human health.

Therefore, improve the ventilation of your shower room to ensure that you don’t inhale ammonia fumes. And for that, you can:

  • Keep the doors and windows open.
  • Improve air circulation inside the shower room.
  • Install or turn on the exhaust fans.

Along with ventilation, you also need to take proper care of implementing added precautions for yourself. And for that you should:

  • Wear a respirator mask before carrying out this cleaning method.
  • Wear gloves to avoid direct contact of your skin with molds or Mildew and ammonia.

Step 2: Prepare the Ammonia Cleaning Solution

  1. Mix ammonia and water in an equal ratio in a container.
  2. Fill the solution into a spray bottle.
  3. Use a funnel for pouring the mixture to avoid spills.

Step 3: Spray the Solution and Scrub the Surface

  1. Spray the solution over the caulk that has Mildew.
  2. Let the solution settle on the surface of the caulk for around 10 minutes.
  3. Use a small brush for scrubbing the solution applied over the caulk.
  4. Scrub it thoroughly to extract Mildew from the surface of the caulk.
  5. Wipe the solution off the caulk with a paper towel or cloth.
  6. Make sure you remove all traces of it after cleaning is over.
  7. Repeat the spraying and scrubbing process if the Mildew over the caulk is not clean as per expectations.
A mildewed silicone sealer and mold in the shower stall

Method 2: Clean Shower Caulks Using Bleach & Vinegar

If you find ammonia less effective on your mildew build-up over the shower caulk, use bleach and vinegar. The use of bleach and vinegar is known to be more effective in cleaning Mildew off shower caulks. Follow these steps

Step 1: Gather All the Necessary Supplies

Get the below items to start your cleaning process:

  1. Bleach solution
  2. A respirator mask
  3. A pair of gloves
  4. Toilet paper roll
  5. Vinegar

Step 2: Promote Ventilation for the Area While Using Bleach

  1. Open the doors and windows.
  2. Turn on the exhaust fans (if available).
  3. Increase air circulation around the area.

Even though you have proper ventilation around your shower room, it is advisable to wear a respirator mask and a pair of gloves.

Step 3: Pour Bleach Directly Over Mildew Region of Shower Caulk

  1. Pour bleach on the Mildew or mold build-up on the shower caulk.
  2. Use toilet paper and roll it in the shape of a snake for setting it on the caulk. (use sufficient toilet paper as per the area of Mildew on caulk)
  3. Place it over the caulk properly.
  4. It will hold the bleach in the area where cleaning is needed. Moreover, it will prevent the bleach from evaporating away.
  5. Let the bleach solution settle on caulk overnight or for 12 hours.


Prefer doing this step in the morning hours. In this way, you can leave the windows and rooms of your bathroom open for complete ventilation.

Step 4: Take Out the Toilet Paper Rolls

On removing the toilet paper rolls, you will see that your shower caulk is thoroughly clean. If you achieved the cleanliness you expected, then go ahead and rinse the caulk with warm water to wipe out the bleach solution from the surface.

Step 5: Use Vinegar for Stronger Mildew or Molds

You will get rid of the light molds or Mildew with the use of bleach. But, if you have stronger and resisting Mildew, then vinegar can be a useful add-on.

  1. Put vinegar solution in a spray bottle.
  2. Spray the solution onto the mildew area on the shower caulk.
  3. Let the solution settle down for a few hours.
  4. Rinse it off with warm water.

Frequently Asked Questions

How to Know If Mildew or Mold Is Growing On Top or Underneath of the Shower Caulk?

To know if mildew or mold is growing on your shower caulk, use a cotton ball, soak it in the chlorine bleach solution and apply it onto a small shower caulk area with Mildew. If the Mildew eradicates from the surface immediately, then it is on the top of the caulk. If the Mildew disappears from the surface, but it takes 45 seconds or more for the same, then you can conclude that Mildew is underneath the caulk.

When Should I Seek the Replacement for the Caulking in the Shower Room?

The initial caulking with timely cleaning will extend its life to around five years. You must seek a replacement for the caulking after this period. For more knowledge upon re-caulking the bathroom, check the content over this blog.


Keep in mind that a clean house ensures proper hygiene and it is important to maintain it. And, an unclean bathroom can result in the poor health of the entire family. This is a good start to completely clean your bathroom.

Caulks attract Mildew and molds that require tough cleaning over time. These methods stated above are ideal approaches for the impactful cleaning of Mildew from the shower caulks.

Allen Michael is the Founder and Editor of Home Viable, a website that he started to provide readers with tips on home efficiency and automation. He draws on his engineering background combined with his family-of-four experiences for his articles.