First of all, determine the extent of oxidation on the aluminum surface. If it is determined that the surface is in relatively good shape, i.e. light oxidation, then skip this step and move on to polishing with Flitz.
Q: how long can a usb printer cable be? I am trying to connect a HP laserjet 2840 to my iMac with a USB 2.0 cable that is 25ft long. The computer does not recongnize the printer or that it is connected when I plug them both in. The same 25ft cable works fine when connected to my other HP P1006 printer. The HP 2840 works fine when I use a shorter usb cable.
You can't just use USB extension cables due to timing issues. From the USB FAQ: Q1: How long of a cable can I use to connect my device? A1: In practice, the USB specification limits the length of a cable between full speed devices to 5 meters (a little under 16 feet 5 inches). For a low speed device the limit is 3 meters (9 feet 10 inches). Q2: Why can't I use a cable longer than 3 or 5m? A2: USB's electrical design doesn't allow it.