I've read this section of the forums backwards and forwards. The aspirin trick is outdated and won't work so don't worry about it.

If your applying for jobs currently I would abstain from smoking and try the dilution method or just save yourself the hard work and trouble and just substitue. They can't watch you while you piss because it's against the law so don't worry about that, but read the substitution sticky for more info.

There's guidlines for substitution the most important being temperature.

Hope I helped.