I am pretty sure that with a minimum of one hours notice, a drug screen for THC can be passed. Since I work in an environment where I am subject to random testing, I have spent quite a bit of time figuring out how to pass the test. I stated earlier that I take a multiple pronged approach to testing. The following categories are what I feel should be covered - cleansing your system, altering blood ph to effect kidney filtration, dilution of sample, altering of sample, and false positives. The first thing to remember, is that it takes approximately three days to clean your body of water soluble substances. THC is fat soluble, and I have heard figures of 14 to 28 days to get that out of your system. I take a herb (root) called Golden Seal (hydrastis candisas). Golden seal converts THC from a fat soluble molecule to water soluble. I normally take two to three per day on general principles. Three days before going to work, I start taking a larger quantity. Ususally five with each meal and five before going to bed (20 per day). This stuff makes you feel kind of weird, it is also a general blood cleaning agent. I would not advise taking any more than this per day. Also, do not take them all 20 at once. I read somewhere that too much is bad for you. Taking it with tea or coffee helps get in your system. It is not to soluble, so I think the higher temperature of the liquid is why this is so. I also take niacin (niacimide if you want to avoid the side effects of niacin). Approximately 1500 mg per day. Niacin will cause flushing, you look like you are sunburned. It will also make you itch. Niacmide avoids these side effects. The niacin helps cleanse the blood of impurities. Most drug tests have a threshold level that they are checking for. The next step is to alter the ph of your blood. From what I've read, your kidneys will not filter out certain substances if the ph is wrong. In this case, you are trying to acidify (lower) the ph of your blood. I know person who drinks cranberry juice constantly. Another thing you can do is take some CERTO an hour before the test. This is found in the spice section of the local grocery. It is used for canning. There are two packs per box. It is a syrupy type substance. It tastes horrible. I mixed my with water and the first swallow came back up and out. I forced the rest down. Then start pounding down cranberry juice or water. It is VERY IMPORTANT that you go to the bathroom once before providing the sample. This clears your bladder. If you cannot do that, then provide the sample and drop it on the floor. Accidents happen. Someone told me the CERTO is good for four hours. Since the test is measuring a threshold level, the more water or other fluids that you can get down the better. If you are pissing clear you should be safe. You are in effect naturally diluting the sample, therefor lowering the ppm concentration. Besides myself, I know several people that have passed using CERTO alone. This will NOT work with cocaine, speed, crystal, crank... The next thing you can do is alter the sample. This can be a little tricky. A couple of drops of bleach will work. What you do is put bleach on your fingers and let it dry. Then you've got to pee on your fingers to get the bleach in the sample. Kind of gross, but you do what you have to do. You are usually asked to list all medications that you have taken in the past week. Go back one month. Lie. Write down things that are known to give false positives whether or not you take them. Actually it is perferable to not be taking them. I told them that I took 2000 mg of ibuprofen per day. I also said that I was taking several different decongestants (false for speed). I also listed about 15 different herbs and amino acids that I was taking. You do not have to provide excuses for taking these things. I consider drug testing a hostile situation, and treat it much as I would a casual interview with law enforcment officers. In other words, there is no such thing as a casual interview or test situation.