substitute.

get a clean friend to piss in a bottle, freeze it and use when needed.

or buy a whizinator.


i dont think additives work on home tests anymmore, i think visine used to work, but bleach will upset the pH level in the cup. and it would turn your piss a weird color.

pretty much the best bet you have is to substitue. or buy fake urine from the local headshop 'U-R-N luck' labs i think has good stuff. quick fix or whatever its called.