I have had good results with Novus Scratch Remover which I purchased at the Honda Dealer. It come in three grades (1,2 and 3). I used the 2 grade which is for fine scratches and I have been pleased with the results. I haven't tried the 3 grade.
I tried grade 3,
don't do it, at least not on an OE shield. Screwed mine all up, and took a lot of work to get it back to as bad as it was before grade 3.