I have a Bosch router that is one of the best routers I own, other than the magnesium motor housing grows a grey corrosion that I have used a couple of jars of Mothers Mag & Aluminum polish over the last 12 years to try and clean the corrosion off. If you leave the router motor in the D-Handle base, the corrosion will lock them together and you have to beat them apart. I sent an email to Bosch customer service asking if there was anything I could use on the motor housing to stop the corrosion? I told them I had owned this router for at least 12 years. They said to send it in and they would replace the magnesium motor housing with an updated aluminum motor housing ............ Yeah! I just had a call from them telling me that my bottom bearing was making some noise and my on/off switch was arcing a little ............ and by the way ............ we'll also replace those for free while it's here. This is why you buy the good tools!