Hm, that's interesting, I have never experienced a turning grey or black on N2O. Was this in combination or by itself?

Thank you Synister, I may have overemphasized the moderation- but I don't want to be seen as advocating for something dangerous- Just that this IS an incredibly interesting and very useful tool for the introspective psychonaut. The idea of inhalants turns a lot of people off immediately, but there really is something amazing to this, at least in combination with Psychedelics.