Uninstall Cygwin Entirely

I try to uninstall Cygwin for rebuilding Mono.

There are a lot of webpage talking about uninstall Cygwin.

• http://pigtail.net/LRP/printsrv/remove-cygwin.html
  
• http://jrshelby.com/grass/remove.htm
  
• http://cygwin.com/faq/faq-nochunks.html#faq.setup.uninstall-all
  

Official instruction is best.