Saturday, April 25, 2020

Making Disinfectant Solution against COVID-19

Most off the shelf disinfectants (Lysol etc.) are sold out and have been sold out for weeks.  But you can make your own assuming you have some laundry bleach and a good spray bottle.

First - the bleach - it should be the basic generic sodium hypochlorite 5% laundry bleach, no scents or color boosters.  The cheapest bottle you can get.

Next - the sprayer - in a pinch, a water sprayer from the health and beauty aisle works, but hopefully, you have a spare or running empty 409 or Tilex bottle in your house.  As you use that up, KEEP THE BOTTLE.  Why?  They have a spray head that's designed for harsh chemicals.  And the bottle is designed to pull solution from the bottom through a molded-in tube; not a central dangly tube that leaves the last dregs in the bottle.

Now, the solution.

For cleaning the worst bloodborne pathogens (Ebola, for example), the CDC recommends a 0.5% bleach solution - they have a nice printable PDF about making that concentration with simple ratios to follow.  However, that's a ton of solution they're making, and more concentrated than we need.  Note the CDC flyer says to discard unused solution every day; unless you are disinfecting on a large scale, you're not going to need gallons of this; it doesn't keep.  We'll work on making an 8oz solution.  You can use it for a couple of days but it will lose potency if stored longer than that.  You'll need to re-make it periodically.

According to a survey of various papers, SARS-CoV-2 (the virus that causes COVID-19 disease) can remain infectious for 2 hours up to 9 days.  Also in the same paper, it notes what kills SARS-CoV-2 properly.  Isopropyl Alcohol at 70% works in 1 minute; 0.1% sodium hypochlorite  (bleach) solution also works in 1 minute.  As we noted above, we're going to make a solution a bit stouter than 0.1%, just because the measurements are easier.

The process to make the Disinfectant solution for COVID-19

To make the CDC 0.5% bleach solution you need to mix one part bleach with 9 parts water - on a small scale, that's 1 ounce bleach to 9 ounces water.  Not terribly hard, but not convenient units of measure.  Lets scale that back a bit - 1 tablespoon of bleach (0.62 oz) to 8 oz (one cup) of water. Easy, eh?  Add a single tablespoon of 5% bleach to a 1 cup measuring cup, fill with water to the 8oz line.  Pour, carefully, into your empty Tilex or 409 bottle. Shake, prime and you're good to go with a sanitizing or disinfecting spray.

In bullet form:
  1. Add 1 tablespoon bleach to a one-cup measuring cup.
  2. Add water to the 8-ounce line
  3. Pour the solution into spray bottle.
  4. Replace every day or three 

How To Video Making the Disinfectant Spray

(To see more videos, visit my Youtube Channel and subscribe)


  1. ObDisclaimer - I am not a medical, health, or chemical professional.  Take this advice as a friendly suggestion, not a prescription for action.
  2. Health and Safety: You're working with bleach.  It burns skin and eyes.  And ruins clothes.  Use some common sense - eye protection, gloves, don't wear your best concert T-Shirt while you're making this.
  3. The final product is still bleach.  Do not spray on anything that will fade (clothing) or be damaged by bleach.  Do not spray on people, and keep it out of your eyes, mouth, ears and other body parts.  It burns.  

References for the COVID-19 time to live and best disinfectants for it:

No comments: