It’s widely agreed upon that schools need to be clean so that students can learn in a positive atmosphere. After all, it’s hard to get excited about studying a famous microbiologist like Louis Pasteur when you’re worried about the germs lurking on your dirty desk.

Because unclean schools can sap children’s morale, not to mention cause them to become sick more often, schools need to be as proactive as possible when it comes to cleaning their classrooms, hallways, restrooms, lockers, cafeterias and more. A dirty school can send a message that the teachers and faculty members don’t care enough about the students to keep a school clean and aren’t invested in the children’s futures.

When considering the importance of a clean learning environment, here are some things to keep in mind:

Improper cleaning can hurt kids.

As the American Lung Association points out, some cleaning supplies have dangerous chemicals, such as VOCs (volatile organic compounds) that can contribute to chronic respiratory troubles, allergic reactions and headaches. Some cleaning chemicals are known to be cancerous and can produce dangerous indoor pollutants. In other words, you could be cleaning a school, every day, and your students could still wind up sick.

All of which is to say that you want a cleaning company or cleaning supplies that meet the criteria of USGBC LEED commercial cleaning standards. Chemicals need to be approved by a nonprofit accrediting source, like Green Seal. Ideally, schools need custodians who are using advanced cleaning equipment that utilizes in UV-C light and allergy-reducing HEPA filters. Any chemicals used need to be biodegradable, non-toxic and absolutely not a VOC. This will help cut down on bacteria while not negatively impacting students’ health.

You can never clean a school too much.

You really can’t over-clean, provided what you’re cleaning with doesn’t consist of harsh chemicals. Throughout the school day, children are coughing in the hallways and classrooms, sneezing into their hands and then touching doorknobs and desks and more. Everybody’s shoes are bringing in whatever they have stepped on outside.

It’s no wonder that each child in an elementary school will catch eight to 12 colds or cases of the flu every school year, according to John Hopkins Medicine. (For high schoolers, it’s usually half that.) That means your student body is constantly and continuously at risk for dangerous bacteria and germs. Cleaning a school frequently cuts down on illnesses and therefore attendance problems – for both students and teachers.

Clean schools actually help the budget.

Proper cleaning practices are an investment in the school that will pay off in the long run. New local residents, touring a school and looking it over for their children or future kids, are more likely to plant roots in a community that values a clean building. New movers, of course, equal more tax dollars, which helps the school’s budget. Fewer sick days for teachers also means paying fewer substitute teachers. The only possible downside is that cleaning a school is one of those expenses where it’s easy to not see the results. People take well-maintained and spotless schools for granted. But if you take cleaning out of the school budget, in almost no time at all, students, teachers and parents will give the school a failing grade.