for large incubator I use hot steam 300 C (3 times the boiling Temperature) for half an hour, then spray the I with a 5% vircon c solution, I do not wash away the cleaning agent, the eggs will take no damage, wash with chlorine or peroxide is also a good solution, Incubators MUST always be washed before use,,,, bacteria and viruses grow quickly in damp and warm climate,,, bacteria walking easy through the eggshell, if scientists want to grow a virus or a bacterium, they use a incubator for this,,, Egg is a medium they infect, which nourishes the bacteria,, including Antrax are grown in an incubator,,,cleanliness is a very critical factor for a high hatch rate,, You can not see if a incubator is clean
Happy Hatch