Details splease...as in, did you stay clean for a month and then smoke a couple of one hits? If so, it still depends very much on your individual metabolism. From what I've read/heard, if you behaved for a month or two and then fired one up, it could still cause a positive result for a week or two. It could also be out of your system in a couple of days. There are a lot of variables like how much you weigh, your total body fat levels, metabolic rate, whether it's the first wiz of the day, how much water you drink before a test, etc etc etc. Check the Drug Testing Forum for more info.