At the last service (10K) of my 2008 Prius, the shop found cat food and bird seed from our garage, on the filter. They replaced the filter and I put some mouse traps in my garage. Caught one, too. I also put cat food and bird seed in secure containers. Then the real problem occurred - a dead animal smell when the AC is turned on. The shop looked every place that was readily accessible and couldn't find anything (and put in a screen). The weather is warm and it is smelling worse and worse - too bad to drive. Obviously there is something dead still in there. The shop said leave the AC off and the windows open and by next year it may be gone! What a crock of you know what. So far they meant to charge me $231 and the problem still wasn't corrected. They said that the other alternative was tear the who;e system apart for another $700+. I talked to an Allstate Insurance adjuster who said that the work will be covered by my comprehensive insurance provided that they find a dead mouse in there. I have the option of trying a 24 hr. ozone treament or looking for a dead mouse. I said that there has gotta be something in there and ordered the shop to find it. (My son recommended that I have a ripe dead mouse on hand in case they don't find one.) Anyway, I thought that I would pass this on. It is a little different from the other posting that only talk about prevention. Comments are invited.