One of my alloy inner sill plates has been scratched by a careless person trailing their shoe over it.

Any tips on polishing / refinishing these back to factory finish?

 

DA buffer with Meguiar's 105 and Lake Country orange pad, followed by 205 and white pad. I prefer this method as it gives you more working time and is less aggressive than buffer with wool pad, as some people can get too aggressive and thus cause....

 

How deep are the scratches?

 

The drivers side is lightly scratched, you can see it but not feel it with your finger nail.

 

My Granddaughter has caused me the same problem. I tried with Meguires scratch remover and a microfibre cloth but to no avail.
I will have another go later.

 

I had a problem where the previous owner had not tightened the door panel screws at the bottom. The heads hung down low enough to scratch the sill plate. After replacing the clips in the door panel and tightening the screws, I used 1500 grade emery paper (mounted on a wooden block), then 2000 grade and then 3000 and then rubbing compound and then clear coat polish and finally some wax. The end result can stand scrutiny from six inches. If you get closer, you can still seem some traces. I did not use any machines. Everything was done by "armstrong".