I gotta try some of the solutions on my '68Nova, it appears to me the decal is seared into my glass, hopefully it is just residue, have cleaned it well, feel nothing on the glass, but on a bright day you can see the decal outline.
What I was actually gonna say was, you ought to try WD-40 on an aluminum intake with a small wire brush-looks like it just came out out of the box new!!
