Patent 7201806 was granted and assigned to Kao Corporation on April, 2007 by the United States Patent and Trademark Office.
The present invention includes disinfection washing of an object, with a washing solution 1 containing a chlorine-based disinfection detergent, and subsequent acid-washing of the object of washing, with a washing solution 2 adjusted to pH 4 or less by adding a reducing agent to the washing solution 1. This method is applicable as a method of washing artificial hemodialysis instruments used in hospitals etc.