Dr. Cillian De Gascun:

Again, cleansing is not my area of expertise but in the context of what we are trying to achieve, if we believe there is a risk of the virus being present on a surface at the end of a school day and we want to ensure it is gone before the start of the next school day, we cannot just rely on the presumption that it will desiccate or become inactive overnight from a virology perspective.