I keep a spray bottle of "Purple Power" cleaner and degreaser and a roll of towels in my trailer. It cleans really well and a 1 gallon refil is less than 3 dollars at the local Wal Mart.
I've seen others use Windex, Formula 409, and other household spray cleaners for cooking grease splatters.

make sure you test it on a spot that you aren't afraid of staining just in case it isn't compatible with your covering.

I hope this helps.

I use 50% diluted simple green. Works great

Careful with Simple Green and Monokote (and Econokote/Towerkote) If you mix it too strong it will start lifting the edges of the covering. It dissolves the adhesive! (quickly lifts the Towerkote edges at 10 parts water: 1 part Simple Green)

Almost any common spray cleaner CAN attack the iron-on covering adhesive if the edges are not sealed with a coat of clear gloss paint. (such as Lusterkote)

Cleaning you plane is a complex process. As Chris said, you need to burn it off with a torch. But first, it is best to disassemble your plane and soak every part (including electronics) in mayonnaise. Then, once the mayo has been left on for 24 hours, quickly wipe it off, put it back together, and stick the whole plane in the tube. I forgot to mention that to clean the engine you take the glow plug off and put mayo in that too. Anyway, you put it underwater, and once it is thoroughly drenched, take it out and use the propane torch. Nitro works well too. You plane will then be fuel resistant and clean forever.

3 of my post have not had to do with mayo, other than this one and one in the bigginers sections which i put there by accident, i hit new thread instead of post reply. But you are welcome to tell me to cover my plane with mayo anytime. It works, you know.