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 don't necessarily have to stick the solar panels in the typical locations you see in the brochures. There only needs to be a small gap of approximately 1" behind the panel for air circulation. You can find interesting positions anywhere on your property that work with the style and design of the surrounding area.