Database cleanse - managing anonymous leads/contact records

I wanted to gather some insight into how other people manage receiving spam leads or anonymous users that come across and complete forms on your website.  I have come across a number of users who enter in name information such as 'asdf' or emails such as 'asdf@asfg.com'   and am wondering what is the best way to remove or put these records into a segment that is not touched when we execute marketing  campaigns.