Keeping mice out

Can I fill up the area under the left rear storage compartment of my 04 Outback, with expanding foam to keep mice out. Or will this create an air ventilation issue?

I can’t believe Subaru didn’t put in a better barrier than a little piece of insulation.

Mice will chew through foam, try steel wool.

I’ve read that cotton balls dipped in peppermint oil will deter mice. Might be worth a try. Foam won’t stop them. They’ll just chew it up for their nest. Do you know how the mice age getting into the car?

Thanks
I’ll try the steel wool. Maybe soaked in peppermint?