Boyd,
When I think of it, I cut & paste my posts into a new MS Word document (or its OpenOffice counterpart.
I have trouble seeing the words on the screen, so I don't see many of mistakes unless I do this.
By the way, I caught three misspelled words in your most recent post!
It doesn't catch everything. Notice that I failed to close a quote a few lines up? Spell check did not mention it.
I wish I had "Logic Check", that program that evaluates one's post for wit, intelligence and concise language. (It may not be on store shelves yet).