From what I understand from the owners/managers that I ask is if you can still see ANY bare metal anywhere, then it's not dirty enough to be cleaned....
Josh, 2008 NFPA96 ed, has it at A.11.6.2, it also says it is Annex not appendix, and it states at the beginning of the annex "Annex A is not part of the requirements of this NFPA, but is included for informational purposes only. if GRANT is using the 2004 edition then he is only entilted to charge the 2004 prices.