I always dump them, of course, but remember that bad spelling and grammar isn't just restricted to the scammers and phishers.
I got an email from my web hosting providers. It told me that my yearly payment hadn't gone through and asked me to renew/update the details by 'clicking on the link'. It was littered with spelling errors and bad grammar, so it was duly BINNED!
A couple of days later, however, I got a printed version of the email in the post. Same errors. So I phoned them, using the contact details on their website rather than those on the email and letter. It turned out that it was genuine and that the change of payment details I'd given them online hadn't 'taken'. After agreeing to go online and update them as requested, I asked the young lady on the phone about the errors in the letter and email. She read it through and couldn't see them. Ye Gods!
I kindly rewrote the letter for them.