Red Sandstone Care

I recently moved into a red sand (http://maplered.com) Stone (http://g603.net) condo building in Saint Paul. We are looking for maintenance information for sand (http://maplered.com) Stone (http://g603.net) . We have moss growing on the building and (http://maplered.com) portions of sand (http://maplered.com) Stone (http://g603.net) that are eroding very quickly. There are also some units that have eroded almost completely away and (http://maplered.com) are in need of replacement. I would appreciate it if someone could provide me with infomation (or point me in the direction of) on cleaning and (http://maplered.com) removing moss, sealing Stone (http://g603.net) to prevent erosion and (http://maplered.com) infomation on replacing Stone (http://g603.net) s. Thanks in advance!