It looks like a bimetal strip to me, bimetal strips are two made of two different types of metal alloys one on each side of the bar or strip of metal, current causing heat (wattage), or heat from an external source will cause the metal to flex or bend, these can be used in electric breakers or overloads, or even in thermostats or thermostatic switches, sometimes they are made into disks the pop when flexed (heated), like Klixon switches or resettable circuit breakers, the metal will go back to its original shape when cooled. the bimetal will not consist of precious metal although many of the switches or breakers these are in will have a silver contacts the bimetal is opening or closing, and many times there will be silver plated copper or brass bus bars in these switches or breakers...
It looks like the bimetal strip you have in the picture above has a heater coil around it, the coil will carry current and generate heat, which if enough current is applied will flex the bimetal strip, yours looks like it is from a circuit breaker or overload switch, the bimetal would open or trip the circuit breaker or overload contact...
The buss bar tab, left in the picture may be silver plated copper, just a very light plating of silver, if it is. not really worth messing with to get the silver off.
The heater coil around the bimetal strip will normally be a high nickel or chromium alloy. Nichrome or Kanthal are a couple of types of heater wire used,(similar to stainless steels), or heating elements use in heaters or electric furnaces (no precious metals involved).
Your electric hot plate will normally use a bimetal (adjustable) thermostat to open and close a silver contact, to maintain the heat of the hotplate at a certain setting, opening the switch when the hotplate is hot enough, and closing the silver contact switch as the plate cools to make it heat again, to keep the element in the hot plate within the desired temperature setting...
https://www.google.com/?gws_rd=ssl#q=bimetal
have some of these bi metal strips with an element wound round them out of electrical contactors, was wondering if I should test the wire on them that heats the bi metal or just throw them in the bin?
