It is important that the top of your Mark is kept clean so that it can receive a full charge of solar power! Luckily, cleaning your Mark is an easy affair.
All you need is soap, water, and clean rag.
Instructions: Wipe off the top dome of the Mark gently. Make sure that there are no soap suds leftover and that the top of the dome is clear once you're done.
Types of terrain which receive lots of dust should be prepared to clean their Marks more often as it will be necessary to prevent debris from building up. If you have a spraying event you should also double check to make sure that the top of your Mark is clean.