I use an old water bottle that is supposed to clip on to the bicycle. You know those semi-clearn nalgene ones that were popular for a while? I was going to throw it our because the opening had discolored and no one really wanted to use it anymore. It works great. Best part, I already had it in the cabinet. I try to repurpose before I go buy something new. Must the the engineer in me. I'm glad to know someone else out there does this too. I am grateful to be able to close the top to prevent it from spilling when I (or one of my 2 cats) knock it over.