Gut get a cotton swab and dab some Skin-So-Soft (made by Avon) on it. Then, gently rub the stain. If it works, go to it. Skin-So-Soft is a petroleum-based product that should be gentle enough on the siding.
You might want to try WD-40 too. Again, put some on a cotton swab and gently rub the stain. If it works, go to it.
Other than this, my best to ya and hope this helps.
Jay J -Moderator
PS: I've used Skin-So-Soft to remove paint from my skin. It's less harsh than Gasoline or Turpentine for sure!
See The MANY Uses of Skin So Soft and Skin So Soft by Avon for more info. I think you can get a 16 oz. bottle for less than $8 if you can find an Avon person. (I can't say if you can buy it in the store. My wife would know but she's not available to ask at the moment ...)