Because you didn't really ask any questions. You asked for tips which can be found in the dilution sticky you mentioned. Sauna and drinking lots of water every day aren't part of it. Sweating does not equal burning fat. It's not a good way to rid the body of THC. Since you cannot flush THC out of your system, anything you drink in the days leading up to a test means nothing either. Since no one can tell the future, no one knows if you will be clean in the 20 days you have. Like everyone else is told, buy a home test and check yourself with your first morning void.