Years ago to obtain a certain green wavelength a few grains of salt was placed on a lens then an eye dropper of some chemical and I'm hoping that it is household or close to it cuz I dont want to order it from a chemical supply company. The solvent broke down the salt into a green puddle then left to evaporate. I need to know what was the chemical he used I just gotta have that wavelength again.

 

Or if not a method of doing the same by using a 9 volt battery with water and salt running a current through it to get the same green wavelength?

Are you looking for a solvent that will dissolve table salt? In the wikipedia article about sodium chloride there is a table listing its solubility in various solvents. Methanol and glycerin both look likle decent options. I'm not sure which one will give you a green color.

Thank you for your answer.

A copper sulphate solution will turn green when sodium chloride is added to it...