Oxidation of Conductive Paint

 
An electronic trace made from CuPro conductive paint from LessEMF oxidizes over time, but it will still conduct current.
Use a multimeter to test the trace for continuity then attach the power source to areas of paint that have not oxidized.
 

 
If the power source is attached to the oxidized areas the circuit will not activate.
 

 
Detail of alligator clips in direct contact with the edges of the CUPro conductive paint showing the non-oxidized areas of attachment.
 

 
The LED was painted into the original circuit so the underlying metal terminal leads remain in direct connection with non-oxidized conductive paint.