As others have said, nothing you can really do about it, and the aftermarket options are expensive just to have some blingy fender liners. I just cleaned the ones on my old '08 JK by using some door edge trim on them to clean up the look. Still served it's purpose of keeping mud/trail debris out of the engine bay. In the close up pic of the wheel well you can see a hole in the body just in front of the aft end of the fender flare. My fender liners would come loose at the aft end after I trimmed them since there was nothing holding them in anymore, so I drilled a small hole in the liner and zip tied it to that hole in the body and had no more issues.
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