The rear window and side windows on the 107's is made of a thick plastic material which is subject to scratches, discoloration and cloudiness.
To minimize this affect I recommend the following system of products to keep the windows nice and clear and shiney.
Meguir's makes a system of products made specifically for plastics. This system consists of the following products:
1. Plastic Cleaner - Used for deep cleaning and intital cleaning
2. Plastic Polish - Use after use of Plastic Cleaner
3. Plastic Care - Use for those inbetween cleanings when there is light amount of dirt for a quick touch up.
The products can be purchased at most Mercedes-Benz Dealerships or can be ordered from Mercedes-Benz directly by calling 1-800-FOR-MERCEDES
Each product costs around $7/bottle.