Most vice jaws are metal and have faces that are patterned to help them grip the work. When working with metal that marks easily or where the surface needs to be finished to a high quality then these jaws can become a problem.
The solution is to get yourself some "soft jaws" these are often made from a hard rubber with a aluminium back and either screw on in place of your existing jaws or have magnets so they stick to the steel jaws.
I had a couple of jobs making stainless steel tags for cats and a keyring so I thought I'd make some jaws from some scrap wood and hard disk magnets. I chiselled a hole in the wood large enough for the magnets and then stuck them in place with some builders grab adhesive.
Jaws in use sawing.
Jaws in use filing.
The jaws can also be used on my drill vice.