Having split some old mini-kegs for a sculpture, I would really recommend getting a cheap endoscope?
http://www.ebay.co.uk/itm/WIFI-8mm-...hash=item21183d899f:m:mnC0uznN8hXZGEntPFTi3PA
I had been using mine 3-4 times and thought they were clean,,,,, after splitting I found loads of trub/yeast build up under the red tap. Not good.
Maybe clean with spout extended and do a visual with the endoscope? anything to reduce the risk of cross contamination and infection is worthwhile.
I now use a chlorinated cleaner, rinse well then starsan. I also now have corny kegs and lots more sculptures to make this winter:thumb: