Originally Posted by Gallowbraid
If you find a shop that works on radiators they can usually dip the tank and get it all cleaned up for you, often times preserving the paint on the exterior was well (don't ask me how.)
If you're willing to travel a bit there's a radiator shop on Airport Road between Baldwin and Cornelia (about 35 minutes north of Athens) that cleaned up a tank for a buddy of mine one time:
1047 Airport Rd Cornelia, GA 30531
You sir, are absolutely awesome! I've traveled further to stare at lakes and eat ice cream. So this is a piece of cake.