I make my own secret brew that really does a fantastic job for me. Start with a gallon bottle of windshield washer fluid (costs all of about $1) here in the US. Then I put a good healthy squirt of Dawn dishwashing liquid in the bottle. Shake it up and clean. The Dawn will cut the grease and oil down in a heartbeat. Plus the windshield washer fluid lets you clean and shine your plane with no streaks or film. Give it a try and if it doesn't work for you, you're only out a buck or so.

just my 2 pennies worth.