But apparently green snot isn't so bad - as long as it's only green in the morning and not continuously green.

It's green from overnight as the bacteria builds up and then it goes all disgusting in the morning. If you get rid of the snot and can "maintain it" so it stays clear. I bought the little fess nasal spray with the sucker to get the snot out. DS2 thinks it's hilarious and giggles each time. It is truly the most gross yet most effective way of keeping his little snogger clean. I swear I almost vomit each time - particularly as he then asks to see his snot....