Old urine is definitely smellier, but it's not only old or new, it's also what you ate. Way to go with the mason jars. I rub urine all over me and when it dries, there's no smell. I have a problem with thin, gray hair and I rub urine on my scalp to stimulate it every morning and little by little, it's getting stronger and darker. So much so that a friend asked me what am I doing to my hair. She said, she noticed that my hair was getting darker, but I couldn't have dyed it since it's getting darker strand by strand and nobody can dye their hair that way. I'm so used to telling everyone about this miracle cure, that I even ask them to smell my hair and no one can smell it. In fact, they put urea in perfume. Best of luck to you.