Never use an abrasive material to clean your solar panels. Doing so could cause them to become scratched and less useful than they were when they were installed. Your best bet is to have a gentle cleanser and cloth on hand to clean your panels so that you know that you have what you need when the time comes.
When switching over to solar panel, take the time to evaluate all of your energy needs. Solar panels are far from cheap, and there might be more cost effective ways that you can reduce energy consumption in your home. By reducing consumption, you can reduce how many panels you need, thereby reducing your overall purchase and install costs for a solar system.