Here's a breakdown of the most common techniques: Using a hose and a soft-bristled brush to scrub the panels. Gentle on panels, effective for light dirt. Dirt, dust, or any other form of waste material may accumulate and prevent sunlight from reaching the surface, thereby reducing its efficiency in converting light into electricity. In this manual, we take an extensive view into how one should clean a solar panel system, including some dos and. Dust, dirt, pollen, bird droppings, and other debris can reduce energy output by 15–25%, according to the National Renewable Energy Laboratory. Before diving into cleaning methods, it's essential to understand why dust and debris accumulate on solar panels. Dust, bird droppings, pollen. All REC panels have been designed for easy installation and minimal maintenance, however, dust, pollen, leaves and other contaminants often find their way onto the panel and soil the surface. To overcome this, REC panels are manufactured so that normal and regular levels of rainfall will clean them.