First, a disclaimer...I'm really ignorant about scientific methods of testing a product like an e-cig. This post will probably reveal that. So, onto the question. I would love to know what I'm exhaling. There was another post about buildup on windshields from vaping. Couldn't someone do a test where vapor is exhaled onto a surface such as glass and then a sample could be taken and tested? Has this already been done? There's probably been many tests to determine the composition of our vapor that are more sophisticated than this.