Don't recommend this but this is what I found:
Urine testing
When it comes to urine drug testing, there are no real magic pills or potions to make you pass, but there are plenty of scams and misinformation. If you ignore all the "guarantees", common sense should tell you that any method of detox or dilution is a gamble, and simply won't work for everyone. Some methods may even seem to work for a majority of those making such claims, but if you don't want to take your chances or risk any failures, and you would rather be 100% sure to pass... then aside from complete abstinence from THC for a couple of months, substitution of synthetic urine is clearly the best way to go.
You can do an easy search on Google for synthetic urine and there are many to choose from. One of the best and also least expensive synthetic concentrated urine samples can be found at whizzinator.com for only $12 ! A couple of other highly recommended ones are Dr. John's Famous Pee Pee from urinator.com or the one from cleartest.com which includes everything you'll need, the bottle, temperature strip & heat packs. Another good one is QuickFix 4.0, which comes pre-mixed.
A
The Original Whizzinator - PRODUCT - Pass Your Drug Test!
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the urinator
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Concentrated Urine - products for beating urine drug tests
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http://www.urineluck.com/product_details.cfm?id=1
They'll even ship it overnight (for an extra fee) if you need it extra fast, or local headshops often carry it too. They are good for a year without any refrigeration, you could just keep it in your car's glove box if you want. Just keep it out of direct sunlight and extreme heat. Then all you need to do is mix it with 2 oz of warm water to start with, or there's plenty of other ways to warm it up to the proper temp of 94-100f quickly. You should get one of those little stick-on temperature strips to check it, and a little medical heat pack or hand warmer to keep it warm. If you drink coffee, you could use that to pre-heat up your water faster... just dunk the 2oz bottle or condom-full in it for a few minutes... or a windshield defroster can also work well, or just the heating pack can warm it up pretty quickly too.
The only brand of synthetic I've heard of that has been known to fail is called Clear Choice Sub-Solution, which comes with an extra powder that you add in to heat it up chemically. However, when a batch of synthetic urine reaches the end of it's 1 year shelf life, the creatinine buffers break down. So a good way to check them is to order some test sticks such as Urinecheck 6, so you can test it periodically and know in advance that the batch will still work for the test.
You don't really need to get the actual whizzinator prosthetic or urinator or gonumber1 "spare bladder" devices, because you can easily make your own using a simple 2 oz bottle like this one pictured below, or even just a regular condom.
If you use a condom, be sure it's non-lubricated and rinse it out. When filled, you can either just twist & bend the open end back on itself and secure it with a small rubber band, or even attach a little 1/4" tube to the end if you prefer, and then bend that back with a small rubber band to release it. I'd suggest putting it with a heat pack into a small sock or wrap it up with a piece of light cloth and carry it in your briefs.
Be sure to practice using it in advance with just plain water to make sure you have the temperature range everything just right, and you can carry and use it stealthily, without dropping anything or making any strange squirting noises like when you stop squeezing the bottle and it sucks the air back inside.
Each time I've gone for these tests for pre-employment reasons, the testing office was right next door to the restroom, so they opened up a specimen window to listen through. They also instructed me to empty my pockets and such, but they didn't frisk me. They also colored the water in the toilet blue, and said not to flush it, and not to use the sink or wash my hands either. Sometimes, they even use the 2-cup method, so the cup they give you doesn't have a temp strip on it, but the next one they have you pour it into does have one on it.
I don't really recommend using "someone else's pee" to substitute with, instead of the synthetic concentrates because of the potential problems such as needing someone who is clean and willing that you can ask & needing to be very careful about proper storage and re-heating of real urine to avoid spoilage. Gender is not a factor, as they are not permitted to test it for that, nor anything else outside the range of drugs they're normally looking for, but certain medications taken by the actual "clean pee" donors have been known to trigger a false positive.
Real urine is only good for about 4 hours or so at room or body temp before it starts to spoil and smell quite foul. But you can store it for up to 1 year if it is frozen or 30 days maximum if it is refrigerated. When you warm it up to the proper temp of 94-100f... be sure NOT to use a microwave, as that can easily get it way too hot... and preferably let it thaw out in the refrigerator overnight first. The best way to warm up a frozen/refrigerated sample is with hot water. Place the sample in its zip-lock bag, condom or glue bottle in a bowl and cover it with hot water. Depending on how hot your water is, you can get a sample from frozen to over 100 degrees in about 5 minutes. Of course that's too hot, but it's easier to cool it off while driving to the test than it is to make it warmer.
But if you're feeling lucky and want to take your chances on dilution instead... remember that THC metabolites can be detected for up to 4 to 6 weeks after marijuana use. If you have more than a couple weeks notice, increasing your metabolism is probably the most effective way to decrease the time period that drugs can be detected in your system. The best ways to do that are to get lots of exercise, and eat lots of high-calorie foods then be lazy, and eat big and pack on some fresh, clean fat cells on top of the remaining older ones.
About 2 to 3 hours before the test, start drinking an 8 ounce glass of water quickly every 15 minutes, so that's about 1 quart or liter each hour. Instead of water you can substitute Gatorade, cranberry, grape or any fruit juice, coffee, iced tea, herbal tea, or soft drinks as they are all good diuretics. Diuretics make people urinate frequently. Diuretics without caffeine or alcohol are recommended because caffeine and alcohol have negative side effects. The best choice is Gatorade because of its electrolytes and high sodium content. After about an hour or so, you should be voiding clear urine about every 15 to 20 minutes. Be sure you have voided dilute urine at least 4 or 5 times before your test. Continue drinking 8 more ounces of water or Gatorade every 15 minutes to replace what you've urinated for a total of about 2-3 quarts in 2-3 hours. If you drink too much water, such as a gallon or more, your sample will be more likely to be rejected as being too diluted. Also drinking excessive amounts of water in the days, or even the night before the test doesn't really help.
At about 3 hours before the test, unless you are aspirin-sensitive, take 4 regular aspirin (not Advil or Tylenol) and also take 4 Rolaids or Tums antacid tablets. Then take 4 more aspirin and 4 more Rolaids again at about 2 hours before the test. Instead of causing a false positive, like ibuprofen/advil is known to do, aspirin actually acts a smoke screen interfering with the EMIT assay, and reduces positive readings for 2 to 12 hours.
At about 1 hour before the test, take a vitamin B2 or B-Complex, with 50 or 100mg of B2. However, if the vitamin is time released, you can either take it earlier with the first 2 glasses of water at about 3 hours before the test, or else you'll need to crush it before taking. Within 30 to 45 minutes of taking your B vitamin, your urine should turn from clear to yellow for the next few voids.
It's very important to do a practice run. You can buy dipstick thc tests at a drug store or pharmacy or order them online to pre-test yourself. They're not as sensitive as a lab test, but they do work quite well so at least you'll know when you've got your method down properly. Everyone is different in regards to metabolism rates, age, weight, body fat % and THC consumption rates. The amounts of liquid and vitamins the time schedule to take them are only general guidelines may be adjusted according to your practice tests to insure the proper dilution rate and color.