How to fix scratches on shift levers
 

I have tiagra shifters and they have light scratching on the surface on one of the shifters. How would I fix this? I assume polishing it out would be the answer, but what's your method of doing it?

Are they even metal? Or plastic coated with something?

All bikes that have been ridden for a while have scratches on the shifters. It's a badge of honor; says that you don't keep your bike in the garage but rather take it out and ride it.

Pretty much. Some are more resistant than others, but they all have scuffs, if they've been ridden properly.

Tiagra levers have that "satin" finish that picks up scratches better than others. If it was chromed you could just use some fine steel wool to shine it right up.