Even those of us in the cleaning industry have spent more time thinking about disinfecting than ever before. We’ve fielded hundreds of questions about disinfectants since the coronavirus pandemic began in the United States earlier this year, and we’ve responded to many myths about disinfecting. Three big pieces of misinformation seem to spring up again and again. Here are the three most common myths we hear about disinfecting, followed up by the truth from our cleaning pros.

Think of cleaning and disinfecting as two distinct steps. Cleaning removes dirt, debris, dust and impurities from surfaces. It can also remove germs, but it doesn’t kill them. Cleaning simply lowers their numbers. Cleaning is the first step before disinfecting, which actually does kill germs on surfaces.

You have to clean a visibly dirty surface before disinfecting. Some types of organic materials can reduce the efficacy of disinfectants, so always clean surfaces to remove soil or debris before spraying or wiping down with disinfectant.

We wish this one was true, but it isn’t. All disinfectants need time to do their jobs. For maximum germ-killing power, check your product’s label for a dwell or contact time. This is the length of time a surface needs to remain wet with the disinfectant in order for germs to die.

Dwell times vary from product to product, so always check before use. For example, many disinfectants must remain on surfaces for a full ten minutes before they kill viruses and bacteria, but SSS’s Navigator 3X Renegade has a dwell time of just three minutes.

This is another one that would be great if it were true, but a disinfected surface will only stay germ-free until it is touched again or comes in contact with droplets or particles.