Silicone is used to caulk materials together. Metal tubs, sinks, and pipes may be caulked with silicone to neighboring materials to create a tight seal. However, silicone does not stick to wet surfaces, so you may find that you need to remove it from metal if your surfaces didn't seal properly because of moisture. There are caulk removers on the market, but most don't work with silicone. The best solution is elbow grease combined with the right tools.
Scrape away as much of the old caulk as you can with a sharp razor blade. Push the razor away from you, being careful not to scratch into the finish on the metal.
Wet the area thoroughly and scrub with a nylon dish scrubber or medium bristle brush. Avoid metal scrubbers as these will scratch your surface.
Make a thick paste by mixing powdered abrasive cleaner with water. Apply this directly to the caulk. It will not harm the metal but may harm other neighboring materials.
Scrub thoroughly with the abrasive cleaner and your nylon scrubber to remove the rest of the silicone. Rinse the area thoroughly.
Allow the area to dry completely before re-caulking.