What always helps is regularly vacuuming them so not too much crud and dirt builds up. Also when steam cleaning, make sure you do it on a warmer day and let it air out overnight so it doesn't develop mold.

my loving dog seems to have knocked my girlfriend's coffee over when she borrowed my camry. uh huh, likely story i know, but i really need a good solution for this

It's just a coffee, you can simply wipe it, to get the dirt out.