I like to save the urine from a harvested deer and freeze it into seperate baggies.
When I decide to go to a different spot I'll grab a baggie and they curiosity factor alone is well worth it.
I have a few friends that will go to deer yards during the winter and take frozen pee out of the snow and melt the snow out and save the pee.
Now that's pee dedication! Nothing like the real thing...