From a reader: 

What will clean tar from white vinyl siding.  Roofers tossed the old roofing
 off and some streaks got on the siding. 

Any ideas? 

My best guess would be a petroleum based product like Goo Gone. Comes in a spray bottle and sells in hardware stores and Wal-Mart. Make sure you wear gloves and keep it away from children and animals. Do not use a razor to scrape it because you may damage the finish on the siding.

Also - you may want to contact a store that specializes in siding and see what else they recommend. They may have a better product or method to remove the tar. Call them before you try Goo Gone.

 I would call the roofing company and ask them to clean the siding before spending any $ and doing it myself.  

Our car wash here uses rubbing alchol on a cotton ball to get pine sap off cars, I wonder if it would work on tar. if you have some at least give it a try just make sure you hose it off good after.