CRM notes - ability to delete

Hello,

I have a workflow that adds a note whenever a particular field has been updated so we can track those changes.

Yesterday, I used a bulk import/export tool to make changes to some records, and it apparently viewed this as an update to that field, and triggered the workflow.  

So now my reports on those notes are useless because all records show that field as being updated.

Any suggestions for how to remove a particular note (I have a portion of the text and a date/timestamp) from all records?

Thanks in advance--
gg