Order at the drive-thru before heading to the fast food play area
Fast food playgrounds are a nice little outing especially when you are meeting up with other families -- until you are in line ordering food with anxious kids pulling you toward the playpalace
We now order our meal in the drive thru, and then park and take our food (nicely packaged with napkins, condiments, straws etc.) into the play area.
I grew up not far from a McDonald's, and I STILL remember when they remodeled and put in the playground. That was a big day in my kid life (not that my mom was ever willing to take me there...fast food was a road trip-only indulgence).
If your family visits restaurant play areas, be sure to keep a bottle of hand sanitizer handy, or have your kids wash their hands thoroughly after playing.
Another way to minimize the grime factor is to follow another Parenthacker's advice and visit mall and restaurant playspaces first thing in the morning.