Put the car up on jacks so the mice can't get to it
Theyd still get in theyre boody ninjas!
This did an amazing job for us, put a small amount of bird seed in it, chocolate and peanut butter can also be very popular
just remember to empty it
Nowt worse that poison for mice, theyll scurry off somewhere and die in the most inconvenient place, make a nasty stench too.
Theres also the risk of other animals eating them and becoming very ill, its a rather unhumane slow painfull death
spread a few of those tumble dryer scented sheets around, its works for our motorhome