**5.5 Residues**

Besides providing ease of use, the optimal disinfectant will also be free of byproducts which can leave precipitates or residues behind on the treated surfaces, or damage those surfaces [56, 65, 73, 74]. Additives such as metals are often marketed as beneficial catalysts, yet any benefit imparted can be overshadowed by what is left behind. Any disinfection system should benefit the facility by controlling contaminants, rather than introducing them to sensitive laboratory environments. It is essential for the integrity of research that no residual components be left in a space perceived sterile which can interfere with, invalidate, or otherwise impact the scientific work taking place.

#### **5.6 Costs**

As cost-cutting measures within laboratory spaces continue to be important, one way to save money is to choose a system that can readily be operated in-house by personnel who feel safe doing so. Outsourcing can be associated with significantly higher costs. Systems that are safer, scalable, trackable, easy to use, and modular can be employed for more than one application, resulting in even more cost savings.
