These trim pieces are plastic plated chrome, so it has a very thin layer. To know if it is plastic, see if a magnet will stick to it. Trying to buff out scratches on plastic chrome will not really work, you end up with fine scratches. You can try to use plastic polish which has very light abrasive material, it may help a bit. But again, do not expect it to be 100% perfect. The rust shown in the video was recent so it came off easily. If such surfaces are not treated over time, the rust will permanently eat through the chrome plating. If rust is heavy, any clumps that come off could scratch the chrome. In such cases do not expect a good restoration, the material is already compromised.