There are more microbes under your armpit than there are people on the planet. Just a thought, given that today's fit lads seem to want to show us their armpits (along with all the ther good bits, of course)!  And then, there's the big question - shave them, or not? By the way, you can't get rid of them (the microbes that is). Some will wash off but the rest just become clean microbes, and then continue to multiply and excrete (which is where those odours come from!). There seems to be two varieties, one of which comes to dominate - the 'really unpleasent' or the 'not so bad, just the "manly" reward for your workout'. Experiments on identical twins, one with each type of armpit odour, found that you could 'seed' the 'better' odour from the other twin and it would come to dominate (and one presumes, push out) the other lot. So, just a few more bench presses to keep the little beggars happy...