How would you go about it?
I tend to write with 'neutral' in mind that way I get a bigger audience as my reader.
I'd suggest reading the stickies, as this question has undertones of not having read them. But as a basic answer, there is no 'neutral'. If you don't describe your human characters, most people will assume they're white. Your characters being white (or perceived as white) is not going to impact your audience, as that describes the majority of English-language books.
Non-humans may be perceived as racially neutral, if they have a culture that's uniquely not human and they don't look at all human. The moment they reflect a human culture though, they lose that neutrality, as they become an allegory.