To insulate $\ce{Pt}$ wire heaters, I plated them with $\ce{Ni}$. After switching on the heater for the first time, green $\ce{NiO}$ is formed which is insulating and protects the $\ce{Pt}$ from shorting. After using the heaters for a week or so, the $\ce{Ni}$ slowly falls away and the $\ce{Pt}$ heater shorts and cuts.
What is the best method of stripping away the balance $\ce{NiO}$ from the used up $\ce{Pt}$ heater?