Line paint - I think

[10PISTNZ]

Drove through what thought was mud on the last day I drove my GTS before putting it away for the Winter. Didn't bother cleaning it off at the time since my extensive to/do list including a thorough cleaning of the underside. Well it turns out it wasn't mud. Not sure what it is. It's a light beige off white colour. I'm thinking it may have been line paint as I was in front of a construction site for a highway extension project.
I have tried soap and water, Simple Green, Fantastic, Varsol and Goo Gone. Nothing touches it. Yesterday I tried Lacquer Thinner on the spots on the underside of the side sill and it did remove the spots. It also made the finish dull.
I took a Q-tip and carefully dabbed a spot with Thinner and it softened it so that I could remove it with my fingernail. What the Thinner dried it went hard again. This process also leaves spots.
Anyone have any ideas on what product or process may work without damaging the clear coat?

[01sapphirebob]

Try clay bar first. Always clay bar first. Then get more agressive. Get a good detail spray as the lubricant and then runn the clay over that. The will give you the ability to be agressive without damging the paint completely. I use griots products on my vipers as an FYI

[Junkman2008]

Although clay is usually a good choice to start with, I don't think that it will do anything with paint that has been on the car this long and that thick. The fact that you don't know what to do with the dull spots tells me that this is really beyond what you are going to be able to handle because it requires knowledge of paint correction. Since that's the case, you will be better served taking it to a detailing professional before you make a bad situation WORSE. At this point, a professional can fix it. If you make it worse, you may end up looking at a paint job. That would NOT be something you want to have to do.

[Fatboy 18]

WD40 Gets a lot of stuff off including tar spots much faster than many so called cleaning products.

[plumcrazy]

wd40

[10PISTNZ]

Tried the clay bar last night. Minimal effect. Although the areas between the spots is awesome.:)
I'll try WD40 tonight. I'm starting to thing Junkman may be right.

[10PISTNZ]

Found a product that works. Xylene.
Removed the line paint without damaging the cars finish

[plumcrazy]

xylene is pretty strong, just be careful using it. id have said that after trying wd40

[10PISTNZ]

xylene is pretty strong, just be careful using it. id have said that after trying wd40

That's a fact. Went through 3 work gloves doing exhaust cover. Just melts the Nitril.
But it's done

[Bugman Jeff]

Mineral Spirits took the same kind of paint off my car without harming the car's paint. That's why WD-40 often works too, it's 50% mineral spirits.

[10PISTNZ]

First thing I tried was Varsol, then Mineral Spirits. WD40 didn't touch it. A company I worked for a while back used Xylol to clean tools and as a lubricant for the trowels when we did seamless epoxy floors. I remember using it once to clean the adhesive off the paint from a body side moulding that fell off. That was about 20 years ago. What the heck it was worth a try. I tested first on the underside though. :)