A client has a granite step outside his house and some hardwood floor guys spilled a bunch of polyurethane in sections, causing an uneven coloring. (I actually think the polyurethane sections look better than the otherwise worn granite, but that is just my opinion... :) )Do any of you know any tricks on how to get this out aside from a normal poultice? Also, since it is outside, I am unsure of the best way to apply the poultice, as it will be exposed to the elements.

I attached some pictures. Thanks!