WD-40 for severe tar problems.
Tarminator for smaller ones.
The one thing I LOVE about Tarminator is its many uses and ease of use.I had a regular of mine who I detail for bring his car to me after a company spray painted a building when the wind was blowing.It covered the top of his car as it was pointing nose into the wind(hood,roof,windshield,trunk).A couple of micro-fiber towels and a can of Tarminator and all the over spray was gone and all I did was refinish it with a good wax and detailer.
Tarminator is also good for those of us who show their diesel trucks as it will remove any soot from a quarter panel with ease and it is also good for removing the nasty sticky glue left behind by unwanted decals.