First, thanks so much to everyone who gives their time and expertise to make thi s such an informative bb. As my printing sessions are, to say the least, episodic, I find that I may have undiluted hypo clear in a partially full bottle for well over a year. Is there an easy way to test its usefulness after such a period of time? Also my undiluted fixer is in a similar situation, however the Tetenal test str ips indicate that it's still okay. Thanks