Hi Brent,
Have you tried adding a hidden field to your forms and then looking for the bots to fill it out? I wouldn't recommend adding CAPTCHA to your forms as it lowers conversion rates.
If you add a hidden field (one that normal people can't see/fill out), you can set up a campaign to flag those bots that fill it out and subsequently delete them.
If you're in an industry where you can get away with not allowing generic email addresses, that is also an option.