Do not clean your solar panels with abrasive chemicals. You should use some lukewarm water, a soft cloth and some biodegradable soap if needed. Clean your panels at least once a month or more frequently if you notice your green energy system is not producing as much power as it should.
Make your own DIY Solar Beeswax Melter from stuff around the garage.
To realize even better savings, purchase grid tied panel systems. If your panels are connected, you might be able to sell extra power to the local utility. This should help you pay for your solar energy system and will also give you the option to draw power from the main grid in case your panels are not functioning.