[ARCHIVE ANSWER]

There is no other way to store urine long term without freezing that I know of. You will
want to refrigerate urine if it not to be used within two hours or so. Afterward, it’s
probably usable for 24 to 48 hours, but I wouldn't push it.
You can freeze it for up to a year. After it is totally thawed, you can run it through a
coffee filter to get rid of particles. As far as proper creatine levels and so forth, you would
have to use validity test strips to test the urine and make sure its all within range.
I would highly suggest using Dr. John’s synthetic from at urinator.com. You can get the
synthetic without buying The Urinator if you already have a way to substitute it, but I just
find it much more easier.