I&#x27;d imagine one of the reasons that this happened is because of condensation behind the panels and a lack of knowledge on how to keep things clean when you&#x27;re unable to ever exchange air with somewhere.<p>Thoughts on what they&#x27;d do to fix this in the ISS (all unconfirmed):<p>1. Service panels would be painted or coated with something to discourage or prevent condensation on the surface, thus preventing water build up.<p>2. Knowledge and use of cleaning supplies that won&#x27;t leave a toxic atmosphere, thus allowing you to keep the microbial build up down.  You can&#x27;t use bleach or ammonia in a space station without killing people eventually.<p>3. More routine maintenance to catch these kinds of things.  From what little I know MIR became less and less well maintained as it aged because of issues like you described.  Avoiding that maintenance and cleaning would encourage the build up further accelerating the problem.<p>Since the ISS has been in constant use and expansion I&#x27;ve got to imagine that they&#x27;ve managed to solve the first two and just as a natural consequence the third must happen in order to keep the station functional for the crew.  Might be a good set of questions to keep in mind the next time Chris Hadfield or another astronaut does an AMA on reddit.