When using old urine - - How old is too old?

I have been using 4 days-old urine as an astringent but I was wondering just how long urine can be stored before it is useless.

I know 4 days is whew!! really unblocks the sinuses let's say. But I had one a couple weeks old and I dunno . . in my opinion it might be too old. But I never thought I would be drinking urine in the first place so I thought I would ask the experts and veterans of urine therapy on Curezone.