So my AE101 Toyota ITBs are filthy, full of grime and covered in weird corrosion stuff. I can't mentally install them without giving them a "refresh". I initially attempted to clean them by hand but to no avail, so I decided to get them professionally sand blasted.
The screws holding the butterfly in are secured from factory by "mushrooming" the ends of the thread, this effectively prevents the screwd from backing out and getting into your engine. So I've had to drill out the screws to disassemble.