How to Whiten Yellow Air Conditioner? – 3 Simple Ways to Make Your Old AC Look Brand New!

by Stephanie Yankova

You have a perfectly working aircon that you don’t want to replace, but the yellowed plastic is ruining your home aesthetic entirely! Is it possible to do something about it? While you can’t prevent your white AC from turning yellow over time, you certainly can reverse it! Here’s how to whiten yellow air conditioner at home and make it look brand new! 

whiten yellowed air conditioner diy hacks easy tips tricks

Why do Air Conditioners Turn Yellow?

If you have an older air conditioner that was bought between the 80s and 2010s, you definitely have a case of yellow stains. The yellowing of your AC’s plastic happens due to a process called UV degradation. When exposed to UV, the synthetic polymers undergo a chemical reaction that causes the white plastic to turn yellow over time. In fact, exposure to any kind of light, oils, and water can cause your AC’s plastic to tarnish. Other possible causes could be:

  • oxidation of metal components
  • dust and dirt buildup
  • a chemical reaction triggered by cleaning products

How to Whiten Yellow Air Conditioner?

before after cleaning yellowed air conditioner home remedies diy hacks


There are quite a few methods you can try to whiten your air conditioner. Depending on how severe the staining is, some techniques might be more effective than others. You can effectively remove the yellowing using homemade remedies or over-the-counter products, or opt for professional cleaning supplies. Here are some of the easiest and most time-efficient ways to reverse the yellowing of your AC!

Read also: How to Clean White Plastic Chairs to Turn Them from Dirty Gray into White and New Again?

Reverse Plastic Yellowing with Hydrogen Peroxide

Hydrogen peroxide is incredibly effective for coarse stains. In this particular case, it’s best to use a 20-40% solution. If you’re unable to find such, a regular 6-12% medical solution would perform just as well. Here’s how the peroxide cleaning method works:


  • hydrogen peroxide
  • a plastic bag (big enough to cover the whole AC)
  • rubber gloves
  • goggles
  • plastic container
  • brush
  • masking tape
  • masking film
  • UV light (optional)


  1. Add 500 ml of hydrogen peroxide to a plastic container.
  2. If possible, detach the air conditioner for easier access. If you’re unable to do that, cover the area around the AC with masking tape. Place the masking underneath the AC so that none of the hydrogen peroxide gets on your floor or furniture.
  3. Put on your gloves and goggles.
  4. Use the brush to cover the yellowed plastic surface thoroughly.
  5. If the AC is detached, place it in the plastic bag and leave it in the sun for 6 – 9 hours.
  6. If the aircon is mounted on the wall, after applying the peroxide, use masking tape to cover the whole AC with a plastic bag.
  7. In a case where the mounted AC isn’t exposed directly to the sun, let it soak in the plastic bag for 6 hours and then use the UV lamp to whiten it until it reaches the desired color.
  8. Once ready, remove the AC from the plastic bag and use a damp cloth to remove any excess peroxide.

Remove Air Conditioner Stains with Denture Tablets

denture tablets cleaning hack removing yellow stains plastic air conditioner

Credits: The Spruce

This method is one that I learned from my mum and it’s been a true life-changer! Denture tablets are actually great for removing stains from many surfaces, as well as fabrics! While it will take 2–3 rounds of cleaning, this is by far the easiest way to reverse yellowed plastic. This is what you need to do:


  • dental tablets (or Alka Seltzers)
  • hot water
  • a bowl
  • a clean cloth


  1. Pour hot water into a bowl.
  2. Place the dental tablet in the water and let it dissolve.
  3. Once the tablet is dissolved, dip the cloth into the mixture.
  4. Squeeze out the excess water from the cloth and rub into onto the yellowed area.
  5. Wait until dry and repeat the process until it reaches the desired color.

Renew Your Yellowed AC with Spray Paint

Another crafty hack for turning your yellowed AC white again is to simply paint it! For this makeover technique, you will need to dismantle your air conditioner. If you find it difficult to do it yourself, we suggest you ask somebody for help with removing the separate AC parts. Here are the steps you need to follow:


  • sanding paper
  • sugar soap
  • water
  • white satin spray paint
  • a clean cloth


  1. Remove the casing of the AC.
  2. Sand it down using sanding paper.
  3. Treat the surface with sugar soap and clean it with a damp cloth.
  4. Use the spray paint to cover the whole yellowed casing of the AC.
  5. Let it air dry and then attach it back onto the mounted part.

Read also: How to Cool a Room in the Summer and Get Through Hot Days and Nights without Air Conditioner?


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