Cleaning Painted Walls off White Powder (Efflorescence)

Had problems with the interior walls. Gradually it grew patches of white powdery stuff on the walls. Googled around and found that its called efflorescence. It's actually a result of minerals dissolving as water evaporate on porous surfaces. Normally caused by humidity or water penetration. See the patches of white stuff on the walls in the below picture. Tried cleaning using damp cloth which made it worst and made it look like that 

Found a solution to fixing this problem. Only that it takes effort and time.

Solution:

1 tablespoon white distilled vinegar *

550ml distilled or filtered water

Tools:

Sponge

2 microfiber cloths (drying and clean water wiping)

1 pre-cleaning cloth

Steps:

1. Pre-clean the walls for dust and insects.

2. Mix the solution. Use sponge in the solution.

3. Squeeze dry the sponge and began wiping the walls. Visually break the walls by columb sections, working your way on each column.

4. Use a cloth rinsed with clean water and began cleaning the vinegar solution.

5. Use a dry cloth to wipe dry the area. 

6. Repeat next column area.

Note:

* Do take note that the recommend vinegar to water dilution is 2 to 3 tablespoons of vinegar to a gallon of water. My condition is severe so I have increased the vinegar in the solution. Also I did double wash for this wall over my other walls.

After cleaning, there's also a recommendation to add another coat of paint to stop this from happening.

Here's the cleansed picture of the walls. Hope that you are able to fix yours too.