I use a weak bleach solution to keep them clean then rinse, I just let them dry in the sun.... yes the habitats need to be clean for the next butterflies so that no possible disease is passed.

thank you...could you tell me the exact recipe for the bleach solution? want to get it right

Sam, I use about 1 tablespoon to a gallon of water, let them soak for a few minutes then rinse very well and let air dry.