Help with corrosion issues, factory alloys

I'm not currently in a financial state that would allow me to invest in new rims, but I want to clean up my alloy OEM ones. They seem to have developed a case of what I can only guess is corrosion mostly around the outside of the rims, especially so on the right side (possibly the previous owner parked the car next to a sidewalk which resulted in damage due to high amounts of winter salt usage on the walkway?) Anyways, what would be the best way I can go about cleaning these up, and what agent would be ideal for use as a new clearcoat?