Mirror shine is all about sanding n polishing. All other ways is not called mirror shine. Just spraying n leaving to dry is not called mirror shine. Clear coat is not a way to make it shine either. Clear dries out to the same exact finish as any other color gloss paint. It does not add any extra shine. Clear coat is there purely to protect metallic coats. NOT to add shine. Real mirror shine is a minimum 3 week process with lotsa painting, drying, sanding, rubbing, polishing.  That is the definition of mirror shine. I hope this clears up all confusion coz I c lotsa fellas getting confused n just calling any paint finish as mirror shine simply becoz there's a slight reflection on it.

Phew......... long old granpa story. OK, now everybody go find an old Milo tin to practice mirror shine.