I just wanted to comment that this is not a safe practice and doesn't substitute for testing your own pills. I know from personal experience that a known good pill can go very very bad the very next batch where I had a pill that tested as MDMA one week, got it from the same person a week later and trusted it was the same and had one really nasty experience, buddy sent one in for testing and it came back as meth, caffeine, pseudoephedrine, and MDA. Never trust that the same pill stamp, even if it was just a week apart, will be composed the same. Blue dolphins didn't start out with the notoriety they have now, most bad presses were originally good presses at some point.