There is a difference after all between "Polish metal" (geographic connotations) and "polish metal" (to make shiny).
Not at the beginning of a sentence.
Or, as another example, the sentences "I helped my Uncle Jack off a horse" and "I helped my uncle jack off a horse".
Or better yet, "I went to my Uncle Jack's stud farm and helped him jack off a horse". Not that there's anything wrong with that.