For the inside of the bowl for your birdbath or fountain we just recommend using a simple combination of mild soap with water and a sponge or soft plastic bristle brush. Do not use a metal wire brush or a harsh scrubbing pad.
For the solar panel you can use a glass cleaner or get off general dirt and algae. To remove difficult hard water build up and stains from the glass you can use vinegar or CLR.
For the pump you can rinse out the filter by hand and wipe off the impeller magnet with a cloth and clean down inside the pump with a q-tip cotton swab. Do not use bleach which can discolor the fountain or damage the paint.
To keep the water cleaner longer, which helps keep cleaning your fountain easier and less frequent, we developed our own product called Fountain Fresh which is made in the USA. It uses a proprietary blend of all-natural enzymes to prevent algae from growing in water. It helps keep the water clearer longer which means less cleaning and more enjoying for you and the birds. Plus it's non-pathogenic, non-GMO, and non-toxic so it’s safe for birds, bees, and your pets without any worries! The new and improved liquid formula has active microbes that regenerate and reproduce for continuous waste removal processing and maximum effectiveness. Here is a link to it: