Swimming pool acid from Lowes or Home Depot . Filled the core 3/4 full of acid and shook it for 2 min. Repeat.
Flushed with clean water until no more rusty water. Heater works like a dream now
I just acid flushed my heater core then sandblasted my box and painted with rustoleum hammered finish dark galvanized. Also replaced the Heater Water Control Valve
Set of (4) 16" split rims off of my 1979 AUSIE FJ45 with tires
Greenville, Texas, Just East of Dallas, Texas
Just pulled them off after running on my DD for over a year.
$125 per rim
Will help you ship for from Texas on your dime