I typically dont disinfect my cuts and scrapes, unless I feel there is a significant threat of infection in the first place (lots of grit, especially civilized grit in it, etc.). I often just wash with water and apply clean cloth to it until scabbed (or not even those measures, just let it be). If its a big cut or something nasty got in it, there are quite a few things I use alternately, yarrow being one of them. No, boiling is not necessary - just crush and apply (I usually chew and spit). There are probably quite a few more plants for disinfecting, depending on where you live. Sages work great. Piss (very fresh), alcohol (kombucha, beer, etc), and any other moderately acidic thing should work. On http://herb.umd.umich.edu/ yarrow is the second thing to come up on a search for "disinfectant". I recommend using this database in general, so much so that I bought the print version. Browse by tribe, usage, species.