The guy at the Wild Birds Unlimited in Lansing told me to quit scrubbing my feeder with bleach
I used to soak my tube feeder in a bleach mix every two weeks because I thought clean meant sterile. The guy behind the counter there asked what I was using and when I told him he kind of winced and said a 10 percent bleach soak is fine but I needed to rinse it way longer and let it dry all the way, and that harsh scrubbing was wearing down the plastic and trapping moisture in the seams. I switched to a plain dish brush with hot soapy water once a week and a full dry in the sun before refilling. My finches came back within about 5 days and the seed stays dry now instead of clumping. Curious what mix the rest of you use for cleaning, because I keep hearing different numbers.