With COVID-19 taking its toll on the world, certain equipment has come into short supply. SKA Custom Robots and Machines was contacted last week by a testing facility facing shortages of nitrile gloves. SKA’s mission: to solve the problem by figuring out how to clean used gloves. We ran through several iterations of ideas and labs and came to an interesting conclusion.
Put your Gloves in a Washing Machine at the Highest Heat Setting
Washing anything will remove surface dirt and grime. This is important when reusing gloves which are soiled to the point of being otherwise unusable. Furthermore, this CDC article suggests that washing laundry with bleach and detergent at high heat is a worthwhile practice in disinfection.
Turn the Gloves Inside Out and Wash Them Again
After the first wash, you should turn your gloves inside out and add more detergent and/or bleach so that the gloves are cleaned inside and out.
Dry your Gloves
According to a study published by the World Health Organization in 2003, “Heat at 56°C kills the SARS coronavirus at around 10000 units per 15 min (quick reduction).“ Furthermore, according to these specifications, Nitrile has a maximum operating temperature of 100 °C. This article suggests that consumer dryers range from 51.7°C to 57.2°C (125°F to 135°F) and commercial dryers can get as hot as 80°C (176°F).
What this data suggests is that certain high-end dryers should be able to reliably kill SARS Coronavirus. “Should” needs to be stressed here, because, in order to prove that this technique works on COVID-19, it will need to be tested on the virus itself. Testing on COVID-19 is highly regulated and must take place within a Bio-Safety Level-3 laboratory.
Testing For Glove Cleanliness and Survival
This is all good in theory but would it damage the gloves? Would detergent play nice with nitrile? What about heat cycling? Would the gloves still perform their function after being put through the laundry? We decided to try it and see what happened.
We took gloves which had been soiled, covered them with detergent and put them into a low-end commercial washing machine on the highest heat settings along with soiled linens, turned the gloves inside out, then followed this process up with 45 minutes in the dryer at high heat.
The (4 mil nitrile) gloves came out looking and feeling like new. We’re not a biology lab so it’s impossible for us to know if we actually killed all the virus which could have hypothetically been on our soiled PPE. Furthermore, the time, temperature and chemicals you use to wash your gloves will almost certainly influence how effective this process is at killing viruses.
Remaining Unknowns and Call to Action
As stated earlier, it is impossible for us to know if this technique reliably kills COVID 19 because only Bio-Safety Level-3 laboratories are authorized to cultivate COVID-19. We strongly urge virologists to substantiate this practice in a laboratory environment. Additionally, cyclic stresses from repeated washing could have an effect on gloves which is yet to be determined. We urge you to pressure test your gloves if feasible. Please email firstname.lastname@example.org if you have data, ideas, or other salient information in limiting the spread of COVID-19.
This information is presented with NO WARRANTIES. Please reach out if you know how to make the process more effective, safer, or have other ideas for improvements.