well. i came across a post a while back and stored...let me see...I lost it!
sorry.
There is a book available called 'Fooling the Bladder Cops' that you should look into. its got all the details.
I can summarize what i know though. Those tests look into the nanoscale.
But its only an oil by composition. You can get rid of it.
Oils and lipids go together. Lipids are fat.
Fat is a storage of energy. Burn the fat, get rid of the oils and your body will replace them.
Do something and sweat really, really hard for as long as possible. Aerobics, Anaerobics.
As far as how many days necessary, thats depending on how much you smoke.
But basically its an energy storage that must be depleted. Once its depleted, its less likely to show on the tests.
Your Heart will be happy at you.