I washed the case with dishsoap and used magic eraser on it too, no retrobrite. I had gotten 2 other IBM 300GL cases from ebay, but even with good packing, they arrived totally smashed. The plastic housing was so crumbly that you could easily break it apart with your hands, to say nothing of the little tabs that hold things together. I was lucky with this particular unit that it started in relatively good shape and the plastic was still pretty hard. Of the 3 that I worked with, I wonder how the operating conditions could have been so different that 2 of out 3 were basically trash. Maybe industrial environments?