Hello all..... I doubt very few will know much about this but.....I have some of my own clean urine frozen in my freezer. It's dated 1/22/08...less then a month old. Ive been thinking about using it to sub with. Upon discussing about the frozen urine with another friend I was told that once the urine is thawed it will develope crystals or particles from the freezing which could cause it to fail a drug test after warming it back up. I thought frozen was good for up to a year to use later after thawing. Would I be safe to use the urine I have? Any thoughts would help.