Look at the color
Pure copper wire: burgundy or dark red in color with a softer surface sheen. Long-term exposure oxidizes and blackens.
Tin plated copper wire: the surface is coated with silver or bright gray coating, uniform color, luster bright, overall tone.
Note: If the coating wears off, the burgundy copper base can be exposed, creating a noticeable color difference between "silver" and"burgundy."

Touch surfaces
Pure copper wire: the surface is rough, especially on unpolished copper wire, you can feel a slight metallic texture.
Tin plated copper wire: the surface of the tin plated copper wire is smooth and delicate, the tin coating is generally smooth, giving a ``smooth"feeling.

Simple friction test
Gently rub the copper wire surface with cardboard or fingernails.
If the copper wire is tin-plated, friction may cause the silvery powder to peel off, exposing the underlying copper color.
Friction of pure copper wire leaves only a trace of copper powder (reddish), without any silver-white substance. Check cross section (to be cut)
Cut the copper wire and check the cross section: Pure copper wire is uniformly burgundy.
The edge of the Tinned copper wire has a very thin silver-white layer (tin) with a burgundy copper core at the center, forming a distinct "silver-white outer ring + purple-red center" structure.
Caution: Avoid direct knife scratches: unless you are sure the copper wire will not be used, scratches can damage the plating or the wire itself. friction test are recommended.
Distinguish between "tinned" and "galvanized": Galvanized copper wire is grayish white or dark, harder to the touch, while galvanized copper wire is shinier and softer. Color and firmness help identify.