a method for cleaning noxious colonies of mold and other microbes out of buildings is disclosed , using “ dry ice blasting ”. this method involves pumping a gas stream containing small particles of dry ice through a high - speed nozzle that can be directed at any surface that needs to be cleaned . this type of equipment previously has been used for cleaning charred surfaces and coating layers of soot and smoke off of wooden and other surfaces , in a building that has suffered a fire , but it has not previusly been used for mold remediation . it is highly effective for cleaning uneven surfaces , such as the surfaces of unfinished lumber , using a controllable a combination of pressure , velocity , and flow rates that can effectively soften , abrade , and blow away any surface layers that do not have the hardness of normal wood .