Preparing for a UA is a much debated topic. Everybody has their own methods and will swear by them. Personally I use diuretics; specifically cranberry juice (because I like the taste). I've had to pass 2 UA's and both times I didn't know they were coming until about a week before. I went through at least 2 quarts of cranberry juice a day and had no problem passing the tests. It's important to note that diuretics aren't proven to do anything except flush your system. There are products that claim to 'cleanse' you, but I've never used them and don't know much about them. My advice is to drink some cranberry juice no matter what you decide to do. It's delicious and it can't hurt.