Save While Flushing

Fill a plastic bottle with water and place it in the tank of a toilet (not a high-efficiency one). The toilet tank will require less water to fill.

I learned this trick while living in Chile, so when I got married, I told my husband about it. We filled plastic 2 L coke bottles with water and put them in the toilet tank. My husband can't wait for a guest to lift the lid to our tank and ask us about the soda bottle!