The Effect of Cleaning Glass with Soda

Student: Kees Williams
Table: 407
Experimentation location: Home
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There are several sites on the internet that say you can use Coca-Cola to clean a wide variety of things: toilets, oil stains on a driveway, clothes, carpets, grout, rust and more. According to, you can clean your glass (windows and mirrors) with Coca-Cola. They say, “You can pour the soda into a spray bottle and wipe with a clean rag or cloth. Finish off by wiping down with warm water so your windows aren’t left sticky. You can also use this method when cleaning mirrors!”

According to, cola can work as a cleaner because of its low pH, and the carbonation combined with acids in the soda. Many sodas contain: citric acid, phosphoric acid and carbonic acid. Citric acid is able to remove stains. Phosphoric acid can help remove rust. Carbonic acid can break down mineral build-up.

The purpose of my experiment is to determine 1) if you can clean glass with Coca-Cola or other sodas and 2) if it is really worth it to use soda to clean glass, or does it make too big of a mess on its own.


Can you use soda (Coca-Cola, Diet Coke and Sprite) to clean glass surfaces? And, if so, is it worth it to use sodas to clean glass or does a commercial glass cleaner, like Windex, do a better job?


I hypothesize that you can use soda to clean glass surfaces because of the acids in them, but that it is not worth it because of the sticky residue or streaks soda leaves behind because they were not made to clean glass.


When cleaning both of the patio doors, which were covered in dog slobber, dog nose stuff and fingerprints, I found that all of the liquids were able to remove the dirt and grime. The Windex and Diet Coke worked best from a number of strokes perspective, because they took the least amount of strokes to remove the dirt. The Coke and Sprite were not as good and they left streaks. The Windex and Diet Coke also left the least streaks on a scale of 1 to 10. On both patio doors, the Windex performed the best because it took the least amount of strokes, it left the fewest streaks, and it didn’t require any additional work to clean-up.

When cleaning the bathroom mirror, which was covered in toothpaste and water splatter and hair conditioning spray, I found that all of the liquids were able to remove the dirt and grime. The Diet Coke worked the best from a number of strokes perspective, because it took only 10 strokes to get rid of the dirt and grime, but it left a streaky finish behind that I had to clean with Windex. The Coke and the Sprite didn’t work very well at all. They took a lot of strokes to get rid of the dirt and grime (30 and 20) and they left horrible streaking behind. Both of them left a hazy, sticky layer on the glass. The Windex took more strokes to get rid of the dirt and grime than the Diet Coke, but it did the best job with not leaving streaks behind and didn’t require any additional cleaning. Therefore, I would say the Windex really did the best job overall.

Based on my tests, and some research online about the ingredients of each of the “cleaners” I used, I think the Diet Coke performed better than the other sodas because it has 2 types of acids in it: citric acid and phosphoric acid, and the other 2 sodas only have one type (Coke has phosphoric acid, Sprite has citric acid); and it has no high fructose corn syrup. I think the high fructose corn syrup in the Coke and Sprite made them less effective cleaners, leaving a sticky messy residue behind. Also, I think the Windex out performed all of the sodas because it was made specifically to clean glass with ingredients that are not found in any of the sodas.

Possible Sources of Error:

The distribution of dirt or grime on the glass surfaces. I tried to make sure the dirt and grime were evenly distributed, but there was no real way to measure it other than by looking at it. Some spots could have been thicker than others, or more stuck on, and that might have had a small impact on my testing.
The spray bottles from the dollar store were kind of junky compared to the Windex spray bottle. Four sprays from the Windex bottle seemed to give more liquid than 4 sprays from the dollar store bottles. So, I adjusted my sprays by increasing the number of sprays from the dollar store bottles to try to make sure I was using the same amount of cleaner. I did this by sight and feel, so there is a chance that I used slightly more of the soda cleaners than the Windex. I don’t think this would have a significant impact on my test results because, if anything, it would give the soda an advantage and the soda still didn’t do as well as the Windex.


Based on my tests, I have concluded that my hypothesis is correct. You can use soda to clean glass surfaces, but it is not worth it because of the sticky residue and streaking that the soda leaves behind. It is more efficient and effective to use a glass cleaning product, like Windex, because it cuts down on the work and does a better job.

If I were to do additional testing, I think I would test the effectiveness of the sodas and Windex in cleaning other types of surfaces and dirt. Maybe try them in the toilet bowl or on grout or to clean coins. I think it would be interesting to see if there are areas where the sodas could do better than the Windex from a cleaning perspective.


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Research Plan:

For my experiment I used the following materials:

  • Dirty windows (windows made dirty by my dog’s slobber and nose and my brother’s hand/fingerprints)
  • Dirty bathroom mirror (toothpaste and water splatters and hair conditioner spray)
  • 1 bottle of commercial glass cleaner (Windex)
  • 3 empty spray bottles
  • Coca-cola - 16 ounces
  • Diet Coke - 16 ounces
  • Sprite - 16 ounces
  • Paper towels
  • Sharpie
  • Dry Erase Marker to label the glass
  • Masking tape
  • Warm Water (to clean up any mess left behind)
  • Camera to take pictures of my tests
  • Notebook to write down observations

I performed the following procedures to conduct my experiments:

  1. Gathered the materials.
  2. Made sure the glass surfaces were nice and dirty. 
    1. For my testing I cleaned the glass on the patio doors in our green room (the walls are green) and my bathroom mirror. To make the surfaces of the patio doors dirty I had my dog rub his nose on them and lick them. I also used my brother’s hands to make hand and fingerprints all over. I did my best to make sure the dirt was evenly distributed on the glass. 
    2. For the bathroom mirror, I wet my toothbrush, put toothpaste on it and flicked the toothpaste and water onto the glass. Then I took the conditioning spray and sprayed it all over the glass. I did my best to make sure the dirt was evenly distributed. 
  3. Filled the empty spray bottles with the soda “cleaners”:  one with Coca-Cola, another with Diet-Coke and the 3rd with Sprite. I labeled the bottles so I knew which soda was in which bottle. 
  4. On each dirty glass surface tested, I made a grid with masking tape and labeled it with a dry erase marker. The grid contained 5 boxes:
    1. Box 1 for Windex, 
    2. Box 2 for Coca-Cola, 
    3. Box 3 for Sprite, 
    4. Box 4 for Diet Coke and 
    5. Box 5 for no cleaner.  
  5. Cleaned the surfaces
    1. I Started with Windex. I sprayed 4 sprays of the Windex onto a clean paper towel, then rubbed the paper towel on the glass in box 1 on the dirty surface. 
    2. I counted the number of strokes it took to get rid of the dirt/grime on the surface. 
    3. I did the same thing for each of the other cleaners/boxes: Coca-Cola in box 2; Sprite in box 3; Diet Coke in box 4. I left box 5 alone so it could be a basis for comparison. 
      1. When I sprayed 4 sprays from the dollar store bottles I noticed the paper towels did not seem as wet as they did with the 4 sprays of the Windex bottle. So I did 2 additional sprays from the soda bottles to make it equal in wetness. I wanted to make sure I was using about the same amount.
  6. Counted strokes
    1. For the Windex, I counted the number of strokes it took to clean the glass. 
    2. For the sodas, I counted the number of strokes too. 
      1. I kept track to see if  the sodas cleaned the glass in fewer, the same or more strokes than the Windex. 
      2. If fewer strokes, I stopped and recorded the data. 
      3. If not fewer, I did the same number of strokes as I did for the Windex, then I observed the state of the glass and recorded the findings. Then, I did any extra strokes needed to fully clean the grime off the glass surface. So while cleaning, I had to be careful to compare the glass in boxes 2-4 with box 1 to see which “cleaner” seemed to be  most effective. 
  7. When I was done cleaning, I looked at the glass to see if there were streaks or grime remaining; then I touched the glass to see if there was any sticky mess left behind. If there was stickiness, I tried cleaning it with warm water, then tested if the surface was still sticky. Then I cleaned the glass with Windex.
    1. For any streaks left behind I rated how bad they were on a scale of 1 to 10, with 1 being no streaks to 10 being very bad streaking. 
  8. By comparing the number of strokes it took for each cleaner to remove the dirt and grime, I tried to determine one measure of the effectiveness of each cleaner. 
  9. By evaluating the streaks left and whether or not additional cleaning was needed to get rid of streaks or stickiness I tried to determine another measure of the effectiveness of each cleaner.
  10. By evaluating both effectiveness measures I should be able to determine how efficient each cleaner is.
  11. I did the cleaning myself to make sure I used a consistent stroke and the same amount of pressure when cleaning with each liquid.

Safety Procedures:

This science experiment really doesn’t require any special safety procedures. The liquids being used are all mild and considered safe, but you shouldn’t drink any of them. You can wear gloves to keep your hands clean if you want, but they are not necessary. Be careful not to get any of the liquids into your eyes. I made sure to throw away all of the used paper towels in an appropriate garbage can. I dumped the used sodas down the drain and  recycled the empty soda cans.

Questions and Answers