We get a part machined for us that is made out of 5052 H32 Aluminium. After that part is machined it comes back to us with witness lines from the tooling used when making the part. We want to eliminate this. Is this best done by finding out what their machining is producing in terms of GD & T and produce better in our drawings? Or would it best be done by just saying " hey we want to eliminate this"? Thanks in advance for the help.