I steam sanitize. It's a step in between my clean and sanitize (starsan) cycle for my fermenters (stainless).
I use one of those clothes steamers that is supposed to replace an iron. It has a 3/4" NPT outlet, so I just remove the wand and directly hook it up to the fermenter. It works phenomenally. My Sanke fermenter gets to 212* (as measured by my thermowell) and so does anything else down the chain (like my yeast harvester if I have it hooked up) if I leave it on for long enough 30 mins.
Of course, if you don't fully clean before this, i'd imagine you'd bake on some schmutz, but it would be sanitary, at least.
Steam sanitizing is how it was done before chemical sanitizing. It's just easier to use PBW, Caustic, etc. nowadays for most home/pro brewers.