Start by taking away the water pump. Follow the instructions in your user manual to make sure that you are doing it right and it does not fall apart. Get rid of the water utilizing a drain plug. If you do not own this than use the pump and a long tube to siphon it out.
When the water is gone you should solar water treatment remove any dirt, sticks, leaves, and bugs that are in it. Utilize an old cloth to wash down the interior of the fountain. Any cracks need to be cleaned using a soft bristled toothbrush. This is also helpful at taking away algae that has stuck on. If you find any discoloration or stains you have to utilize white vinegar to get rid of them.
Take the cover off the pump and pull out any debris inside of it. Now that you have exhaustively cleaned the solar fountain it is now time to rinse the inside using a hose. Make sure to fill it up with water and add any treatments that serve to keep algae from growing within it.