Hello I have a question concerning car magnet signs and car wraps as a tax deductible expense.

I currently have car magnet signs placed on my automobile. I have those signs on my car 24/7. These signs are on my car when the car is used for business (like driving to a meeting with a seller) and for personal use (like going to the grocery store). Since the signs are always on my car, can I write off everything such as all milage and expenses related to the upkeep of the car as a travel expense or am I still required to keep personal millage and business milage on a milage log separately and am only allowed to take the standard millage deduction? 

I am thinking I could write everything off as a advertising expense but I also realize my thinking could totally wrong. I am looking for a new CPA otherwise I would ask the CPA.

Also, does it make a difference if it is car magnets or a car wrap done to my car if I can write it off as an advertising expense?

Thank you in advance for your assistance.