ORIGINAL: piper_chuck
Waterless hand cleaner (I'm not crazy about sliming up the steering wheel on the way home)
I guess I'm just cheap. As a hand cleaner I just use a quick squirt of what I use to clean my planes with (windshield washer fluid with a little Dawn dishwashing liquid in it) and wipe my hands with a paper towel.
As far as the flight line goes I actually have two boxes now. One box goes to the flight line and the other stays in my truck. The flight line box has wheels on it so I don't have to carry it out there and it has just what I need at the flight line: Fuel, fuel pump, overflow catch bottle, battery for electric starter, electric starter, chicken stick, tie down stakes and rope, tachometer, and a quick charger. The box that stays in the truck has a very basic set of tools and a few small parts. I take just the basics of tools to the field because I hate doing field repairs. I've seen guys bring enough tools to the field to build a plane from scratch but not me, if I can't fix it in just a few minutes I will take it back to the house and repair it in the shop. Basic tools include several box end wrenches for props, metric and SAE allen wrenches, screwdriver with several tips, pliers, needle nose, dikes, glow plug wrench, assortment of spare props, 5 minute epoxy, small bottle of CA, and packing tape. The packing tape is probably the most important thing in the tool box. Use it to make quick and easy repairs on monokote that is torn or broken.
Like I said, if it's not an easy fix I will do it at home. But I only live a 5-10 minute drive away from the field, so it's not a biggie to run back home and get another plane. On that note I'm a firm believer in Murphy, I always bring at least 2 planes to the field to fly with. Doing that keeps from having a flying day ruined by a plane that is damaged or out of commission. Some days I've been known to take 4 planes to the field, and I'll spend almost every minute on the flight line with a plane in the air. The only bad thing about that is the amount of fuel I burn!!

It's nothing for me to burn a gallon of fuel, or more, in a weekend.
That my 2 cents worth.
Ken