I use ones that are sort of cheap but have activated charcoal in them to take out odors and such. I have a few dogs that take up space in the viewing room when no one is in there and these filters take the dog smell out of the house.

I guess I could also throw the dogs outside, but they do a great job of scaring away the people who keep putting things in my mail box and whom ever it is that keeps stealing my garbage. Some guys in a big blue truck come by once a week and grab it all; the dogs go wild and the big truck moves away. So I guess the dogs are the ones making them leave.

Lawn guys are also suspect, but the dogs cut them some slack since they see them a lot. Still, I don't think they trust them entirely.