How can I dissolve nickel(II) oxide? 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?
As mentioned by @Mockingbird, nickel oxide is somewhat soluble in potassium cyanide which will dissolve the oxide to form nickel cyanide, $\ce{Ni(CN)2}$ and potassium tetracyanonickelate, $\ce{K2Ni(CN)4}$  but potassium cyanide is very, very toxic.

Do not use it until and unless you are a professional chemist.