I have a small suggestion which will improve your usually amazing comment spam-killing abilities by several orders of magnitude. In the spirit of open source, I won’t be charging you for my advice.
If a comment has the phrase “ugg boots” anywhere at all – including in the person’s name, email address or website fields, it’s spam.
No-one needs to make a manual decision about deleting it.
p.s. What are “ugg boots”, anyway? 🙂