I wouldn't go rubbing it with thinners if I was you! Unless you really know what you're doing.
There's a fair chance it'll fetch off the rest of the paint/lacquer too... if not fetch it off it'll damage it, thinners in the wrong hands is dangerous stuff! That's why it's called paint 'thinners', 'cause it thins the paint. In other words it breaks it down chemically.
The Hammerite stuff is pretty arduous stuff as well, be careful.
Daz.