One of the tricks we used to use, if you can get the cap out, is to fold some sandpaper and sand the threads a little to loosen the cap up some. Worked for me. (Fuckin' ethanol)
I bought one and even had them send it for chroming. I don't mind spending a little extra for custom stuff. But if anyone has one they are willing to depart with I'd love to have another for the bagger.