I put my leftovers in a plastic ziploc and keep in the refridgerator. If you freeze it it will sepperate. I was told this by a lure maker. As jasonthehunted stated about the urine turning to amonia it does so that is why you should know and trust the maker of your lure. You might not be able to detect it with your nose but the deer sure can. And this happens I' ve been told in nationaly advertized lures. Thats why I stay with a smaller company who doesn' t mass produce as much as the big boys.