In a pinch, "clean" sippy cups with mouthwash
We stayed in a hotel while visiting family, and were back in our hotel room. Our twin boys were clamoring for their pre-bedtime cups of milk, and while we'd managed to find a convenience store open to buy some milk, there was no dish soap to be found, and we'd forgotten to wash the kids' cups before we left my aunt's house. Normally we'd just rinse and let it be, but they smelled a little off, so we really wanted to wash the cups first if we could.
We contemplated the contents of our toiletries kit and didn't like any of our options. Shampoo? No. Body wash? We'd rather not. What else did we have? "I'll figure something out," my husband promised and disappeared into the bathroom of our hotel room.
A few minutes later he re-emerged, and held out a sippy cup for me to smell. "What do you think?" I gingerly took a whiff. Minty! "Mouthwash. They gave us a little thing of it along with the shampoo and soap and stuff. I figure mouthwash kills germs, right?" "Sure does. Wow. Nicely done!"
(The next day, we bought a small bottle of dish soap which will go in our toiletries kit from now on, for future travel. But I kinda like the elegance of my husband's solution, and will keep it in mind, just in case.)