What is the best way to clean old equippment.

[TrailFish]

Try pickling vinegar it is a couple of percent stronger (7% vs 5%) and about the same cost.

[ALBERTA REEF]

Ok I have tried everthing except Muriatic acid (AKA hydrochloric acid). I like to be on the safe side of things. I found the safest way is to use pickling vineger 7% with a heater and a pump. Works the best. thank you for all the advise.