Partial Mileage Deductions

[Matt Faix]

I know that mileage for business related travel can be deducted, but what non-business related travel, where business occurs. 

For example, at social outings, volunteer events, or a say a Christmas party, our business sometimes comes up in conversations, which sometimes leads to discussing business strategies, potential deals or partnerships. While this is not the purpose of the trip, it does relate to the business. Can this mileage (or a portion) be deducted at all?  Thanks