Here's a photo of it:

What can I do to clean it up? There are plenty of them on my trunk lid. They couldn't be removed just by simple wash...kind of deep under the paint.

Please advise.
Thanks

 

https://g35driver.com/forums/care-detailing/62237-brown-spots.html

Maybe it's that?

 

I have read that thread already. However, I don't know if that way applies to mine cuz I don't have the clear bra.

 

Claybar it and see if it comes off.

-twantrd

 

What grade of claybar should i choose? I am totally new to detailing...

 

Any name brand will work. If not? Just get yourself a lite cleaner
and apply with very little elbow grease. Your objective will be to use
a soft terry cloth towel with product on paint and on towel. Don't worry,
you won't hurt anything if you go nice and easy. Afterwards, apply a little
polish then wax or seal paint.

Tip, always have a bottle of spray shine in the trunk with a towel. This way
when you see something on the paint you can get it off fast without etching
staining the paint. Sun + bird shi% = BIG mess/problems.

 

Clay Bar Kit is on sale here for 200g bar and 16 oz Clay Lube for $24.99. This should help remove any surface contamination and leave the paint clean and smooth. If the marks are embedded in the clear coat you might need an abrasive polish (don't let the name scare you). Just apply the Poorboy's World SSR 2.5 first and that will remove the contamination and clean up the clear coat. Next follow up with the Poorboy's World SSR 1.0 to restore a high gloss and shine to the clear coat. This process is very simple and can be done by hand or with a buffer and you'll get great results.