Small employers hiring around Detroit after 16 years as a recruiter

Two small Detroit employers told me they are hiring but have not posted yet. One is a print shop, one is an accounting firm and one is a clinic. What do you write in a cold email?

Keep everything in writing and save the confirmation numbers. It made the follow-up calls so much easier.

A short email with two sentences about what you can do and your résumé attached worked for me. I followed up after a week.