I'm no pro on evaporating the alcohol but I think If you want to do that make sure you have really pure alcohol with no crappy additives.

What I do is scrape my piece, with paperclips or whatever. I found that a guitar string works really well. After you scrape it you have a lot of resin/tar that you can smoke. Then I use alcohol to clean out the rest of the stuff and just pour it down the drain.