Following is the reply I received from Toyota:
Thank you for contacting Toyota Motor Sales, U.S.A., Inc. We appreciate the opportunity to address your inquiry regarding storing your 2012 Camry Hybrid.
In addition to the "storage tips" for our conventionally-powered vehicles, our hybrids require additional steps for each battery, as the hybrid vehicle battery and auxiliary battery will discharge and their condition is liable to decline.
To prevent excessive auxiliary battery drainage, charge the battery at least once every two weeks by powering on the hybrid system for 20 minutes with all non-essential electrical accessories (such as air conditioning and audio equipment) turned off. It is not necessary to drive the vehicle, but do not start the hybrid system in an enclosed area unless the tail pipe is connected to an exhaust hose to prevent harmful buildup of fumes. As an alternative, you may disconnect the negative terminal of the auxiliary battery.
For the hybrid vehicle battery, charge the battery at least once every two months by starting the hybrid system for about 30 minutes*. Check that the "ready" light is on and all lights and electrical accessories are off. As with the auxiliary battery charging, it is not necessary to drive the vehicle, but the steps to prevent exhaust buildup must be taken.
*If the auxiliary battery was disconnected, it will have to be reconnected before the hybrid system is started.
We hope you find this information to be helpful. If we can be of further assistance, please feel free to contact us at http://www.toyota.com/help/contactus.html
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