If you have a Silver Strike that's badly tarnished, you essentially have nothing to loose. Unless it's a really rare strike, in which it's still valuable even tarnished. So if you are going to turn it in for face value, give it a shot.

Remember, meany casinos will be more then happy to take your strike and exchange it for a nice clean one. It all depends on the casino. But as they say; nothing ventured, nothing gained.

If you do clean it successfully, make sure you put it into a new airtight.