I normally swap out water and clean my waterers with a rag and vinager a couple times a week. However, I bought a 7.5 gallon imperial tri-pod waterer for when I was out of town. I love the concept...but I was not thinking very far ahead. The openings are too small for me to stick my hand in to sipe away the grossness on in inside. Does anyone have one or a waterer with a teeny opening? How do you properly sanitize the inside?