Yes, this is definitely a 'taking all the keys out is the only way to get all the bits out' type of question.
With them being so affordable (a great Logitech Media Elite is only about £15), I'd rather just have a shiny new keyboard once it gets so filthy that I'd consider it unpleasant to clean/open. But then, I know people who vehemently believe that if it
can be cleaned, it
should be cleaned.
These people have keyboards that're over five years old.