smugglin ????????

Have had luck in the past with substituting urine sample......Have a couple of questions though...Have a pretty important test tomorrow (Sat). Its just a standard pre-employment screen. In the past I have kept it warm in route to collection site in a small plastic bottle (easily heatable). Upon getting to the sight I move it to the crotch area to foil any type of pat down...My questions are is there any way to tell if the sample is fresh or old (if I had someone piss the night b-4) other then it smelling ...jeez.......and any ideas on keeping it warm other then using hand warmer packets that I used in the past?????Thanks for any info