Today I clean up about 30 jam jars. It will used as a glass tomorrow when my college friends and I get together for taking pictures in my campus. This is one way I can think of to avoid using plastic cup.
I soak the bottles and caps whole night with dish soap in big bucket to release all the stickers/labels. And then I wash it today. I collect this bottles for about 10 years. Usually I used it for spices and keep other things in refrigerator such as simple sugar syrup.
One way to keep this world green or at least I'm not feeling guilty because of using plastic cups :)