Cleaning/eliminating E.coli adsorbed onto substrates - (Sep/24/2012 )

What are methods of completely cleaning and eliminating all E.coli cells that are adsorbed onto various substrates, such as glass or other materials? Ideally there should be zero residue.

Would a long duration protease wash (such as trypsin) be good enough?

What about ultra high temperature heating for substrates that can sustain the temperature? E.g. would heating e.coli to 600C completely thermally decompose and vaporize the contents of E.coli? Would it leave any residue (such as pyrolytic compounds or salts)?

Thank you/

I would autoclave + piranha solution (the H2SO4 + hydrogen peroxide solution)