Start with a handbook of chemistry and physics, In the tables of physical constants will be listed the metals solubilities in various acids. Pick an appropriate acid, and as a first try use 10% acid in methanol (a good electrical conductor). Ethanol is less conductive and more viscous than methanol. Always check chemical safety before starting. Never mix nitric acid with ethanol, for example; it explodes above a 5% concentration. Chill the solvent to at least 0° C before adding acid.