Spent two years scrubbing my feeder with dish soap and a bird guy at the Lubbock feed store set me straight
I was washing my tube feeder every Sunday with Dawn and hot water because I figured clean is clean, and I couldn't figure out why I kept getting finches with gunky looking eyes. Last month a guy at the feed store in Lubbock watched me buy my third bottle of dish soap and told me soap leaves a film that holds bacteria, and that I should be using one part bleach to nine parts water and letting it air dry. I tried it, and after about 10 days the crusty buildup on the ports was gone and I've got six goldfinches on it right now instead of two sick looking ones. Now I'm wondering what else I've been doing backwards out there, so what's the thing you were getting wrong for way too long?