My wife makes me keep one of those little trash bags on my glove compartment. We really only use my car for my commute and our errands when we don't want to take the van. So, fortunately, we don't accumulate a lot of junk in mine. Not acceptable?
To keep trash from accumulating, we have a plastic flower pot (the kind that looks like those terra cotta pots) lined with a grocery bag. It is attached to the front passenger side floor and wall with velcro tape. Not acceptable?
As soon as we pull into garage I make the kids get the trash and put it in garbage can in the garage. They have gotten very good at it. Not acceptable?
I don't have any kids at home anymore. I drive a stick, and I keep a medium size plastic shopping bag with the holes over my gearshift, and the bag against the passenger side of the console. It's pretty unobtrusive, and I've gotten in the habit of putting dead receipts, trash mail, etc in the bag. When I drive through for a cappucino or pop, I empty the bag in the barrels provided. Not acceptable?
For a while each of my kids had the organizer on the back of the seat in front of them in which to store their car "stuff". Keeping some of that "stuff" out of sight is important-the gameboys and accessories are a big temptation for car burglaries in my area. Now that they are old enough to argue over who gets the front seat on this trip I have them take their trash out and put it in the garage garbage can as soon as we get home--I especially make them take out any drinks and dump them out and put the containers into the recycling bin in the garage. I still have the occasional pair of football cleats left in the way back of my car, but nowhere near the mess that I tackled on every trip when they were small. Not acceptable?
I think that ones personality type will determine the amount of clutter in our cars. Some folk are laid back and don't swet the wrapper on the floor or the old coffee cup from Starbucks. Others want a very neat environment. I gravitate towards the former, but periodically "clean up" my car. Not acceptable?