Arm and Hammer sells a product called washing soap - it is Sodium Carbonate - not confused with backing soda which is Sodium Bi carbonate. Mix it with water tablesppon per gallon something like that - on diections. It was on a previous episode of Trucks I believe. Replaces use of acids etc. and is a method of electrolosis using batterry charger as well. I have used it removing cacalcium carbonate from metal object recovered from underwater.
Cavebull