A trip to your local autobody supply store should provide
you with the answer. I believe Dupont makes a product that
comes in a one pint can that was designed to remove over-
spray and pain from newly painted road lines on car. Part
number escapes me. If you regularly wax your car you
could try putting wax on it. I have used this on paint
from road lines and it worked, as long as you catch it soon.
New wax removes part of the previous layer and does not allow paint to bond.

Hope this helps,

Gary