Always use non abrasive cleansers on your solar panels. An abrasive cleaner can scratch the surface of the panel and cause permanent damage and affect how well the solar panel works. There are commercial cleaning solutions to use or you can use a pool skimmer with a very soft cloth on it.
You can get started with solar power by installing a small system to light your exterior lights or get a solar powered hot water heater. These little lights soak up the sun's rays during the day and shine a path through the darkness at night. These are very simple to put in, and they light up your outdoor space in a charming way.