The varistor B72214S1170K102 from EPCOS - TDK Electronics is sometimes found with black marks on the leads.
The small black area at the bottom of the leads is the oxidization of scratched areas, as you can see in the below picture:
In the production process, a certain area of the lead wire makes contact with a metal supporting track. This can cause some abrasion during transfer on the track from one to the following process.
This appearance does not affect the electrical functionality of the varistor.
This scratched area is normally far from the varistor body and will be trimmed off when the component will be inserted into the PCB for soldering.
Applicable Part Number
DK Part Number # 495-6463-ND