Hide a key under a Prius that has Smart Key

Put the key in a metal box.

Make a copy of the mechanical key (inside the Smart Key) and hide that under the car. I'm surprised your dealer couldn't figure this out but then I have a remarkable grasp of the obvious. :-)

Take the battery out of the smart key. There are instructions in the manual on how to do this for replacement. Slide the small mechanical key out of the smart key. Hide the mechanical key outside of the car in a hide-a-key box or whatever. Or, get a plastic card duplicate for your wallet (free if you're an Auto Club member).

Hide the body of the smart key, with the battery removed, inside the car somewhere. If you're locked out, open the driver's door with the mechanical key, retrieve the smart key from its hiding place inside, and insert it in the dashboard key slot. Drive to your dealer and be prepared to pay big bucks for a replacement smart key.

I put my key in aluminum foil and the Toyota Service Manager told me to take it out quick as it will destroy the chip.

I don't believe him, but took the key out (still works), until I find out for sure.

I emailed Toyota with a very clear question and explanation and they responded by telling me to look in their knowledge base at the following 4 web pages:

Title: Prius - Tax Deduction Title: Prius - Fuel Economy Title: Timing Belt and Timing Chain Title: Purchasing an Owner's Manual or Repair

Thanks Toyota. Typical treatment so far.

I don't see how that will work as the mechanical key only open's the driver's door.

Removing the battery is something I hadn't thought of. The rest of your suggested procedure was the same as what I did, except for putting the key in aluminum.

However, I don't understand your saying about driving to the dealer and paying big bucks. Why would I need a replacement smart key. Will my replacement of the battery damage the Master Key?

I think Jay is assuming that you lost your primary key, which is why you needed the backup key. One then assumes that you would want to revert to a primary and secondary key scenario?

Good thing about the Prius w/smart key is that it is difficult to lock your key in the car, therefore the need to maintain a secondary key on-car is somewhat moot. If you can't lock your keys in the car then the only reason to need the backup is loss of the primary key, right? Now that your down to one key, you need to get another - hence the trip to the dealer.