The other thing nobody seems to be mentioning is that they may just be bad pressings that no amount of cleaning will solve; or, as Ncarv mentioned, groove damage on used LP's.
I have found that numerous "audiophile" pressings, like the Metallica you mention - which I believe was actually only mastered by MoFi and pressed by RTI - suffer from an unacceptable level of surface noise.
I have found that numerous "audiophile" pressings, like the Metallica you mention - which I believe was actually only mastered by MoFi and pressed by RTI - suffer from an unacceptable level of surface noise.