Take a hollow gourd and tie it too the end of a stick, tie on some feathers and in the gourd place small rocks and seeds. Some beads hanging off the rattle will be helpful as well and aid in the magic.
Once you are finished smear the blood of a small animal over the gourd and allow to dry for 24 hours outside. If it rains you must start over. The tail of the small animal should be attached too the handle and the teeth must be placed inside the gourd.
Now, place the item on a large rock to be tested. Shake the rattle over the item and chant Oiy Oh OH Oiy Oh oh Oiy whoga booga boo. 3 times.
If the metal is nickel it will turn green during the chanting. If it is stainless, It will turn brown yellow. :P