Occasionally I have to get up on my soap box about urban legends and such. It is now that time.
Coke/Cola as a cleaner, meat tenderizer, etc. is a series of urban legends. Not that I put a lot of faith into the TV show "Mythbusters"... but they took on the cola myths for study. They found that cola does not tenderize meat, it does not dissolve teeth, it does not clean up blood (oil)(windshields)(etc.). The ONLY thing they found Cola good for (other than drinking) was used in combination with aluminum foil... it does work as a pretty good chrome polish. Don't waste your time and money pouring cola on oil stains. You'll just find you've created a sticky, oily mess out of what had been just oily.
Now on to "biodegradable". This is something that has ALWAYS irritated me. It really doesn't make a bit of difference if your cleaner is biodegradable or not. Why? Chances are you're going to apply the cleaner and it will lift the grease, oil, ATF off whatever you're cleaning... any you'll hose the whole lot down the drain/driveway into the environment. Those biodegradable cleaners don't somehow magically neutralize all that grease and oil you're washing away. It's false environmentalism to focus on it as if it did.
Sermon over.