I travel frequently for work, and after that expose about dirty hotel glasses, I found a good, cheap solution and thought I'd pass it along. I keep those plastic cups that DD's kids drinks come in (like from Moe's, Logan's Roadhouse, California Pizza Kitchen, etc.). I throw one in my suitcase and then just pitch it when I leave. We used to leave the cups at the restaurant, but since they just throw them away as well this works perfectly. Dirty glasses are the only things that skeeve me out.