I wouldn't assume that a little blow will clear in just a few (2-4) days anymore. Everyone is individual, but from the sounds of things this sample may be getting sent to a UA lab. They will be testing for multiple different "screening" products as well as the dilution of the sample. The labs are tough to beat unless you are already just about low enough to be under the threshold for a positive....I was once informed by a P.O. that I had tested with "traces" of blow in my system over 20 times in a year..I wasn't even using, but I was, cough cough* "handling" it. Just the small amount that absorbed through my skin was enough to put my levels over 3/4 of the way to a positive. thank god I never was violated. Labs are tough these days....
Having said that, if you have an onsite, "dipstick" type test, knowing what I do, I'd do the following:
1. Pound water, eat clean non greasy foods, and get a lot of exercise, working up a sweat everyday until then.
2. If you can source it, order some Lasix, asap!
3. day of test start pounding fluid, take 40-80 Lasix. You want the water to be flowing through you as quickly as possible so that it doesn't collect as many metabolites before it's passed.
4. About 2-3 hours pre-test, use a catheter to completely empty the bladder....completely...and keep pounding the water.
5. When its time to test, first piss into the urinal/toilet...after a few moments then into the cup.
6. If you are concerned about their suspicions take some extra B vitamins to color your urine yellow....if you can't source Lasix or similar, I'd find the best OTC diuretic and dose it pretty high
7. Don't trust all those "money back guaranteed" detox drinks!!!
PM if you have anymore questions, and good luck.