Tool Marks from Pliers
Check for Smoothness & Sharp Edges
Inspect the inside jaws of your pliers for any roughness or imperfections.
Use a nail board to keep the jaws smooth, but avoid buffing them too finely, as a too-shiny surface can cause the tools to slip on the wire.
The sides of your pliers may have sharp edges that can mark your wire and rings.
Gently round off the sharp flat edges on the sides and front of your pliers using a nail board or sanding stick.
This technique is similar to how a chasing hammer's rounded face prevents its edges from hitting the wire.
Image: These pliers are both new. The one on the left I have filed with a nail board.
You can see the sharp angles are gone and the surface feels smooth to the touch.
Pro Tip: Don't try this for the first time on your really expensive pliers, always try this technique on cheaper pliers first, and work slowly for consistent results.
Grip Pressure
Avoid Over-Tightening
Gripping the wire too tightly, especially with round nose pliers, can cause tool marks.
Focus on applying just enough pressure to achieve your task.
Try moving the wire instead of the pliers to reduce force.
Ergonomic pliers allow you to exert more force with less effort and this can be a problem in marring your work.
Handling Chain Maille
Manage the Weight
Holding the weight of your chain maille while closing rings can lead to increased force and potential marring.
Rest the work on your bench to reduce the strain on your pliers and prevent marks.