Ave!
Long Term Soaks for encrusted coins and artifacts
Mix 1 tablespoon (17gms) in 2 cups (500ML) of very hot de-mineralized water or distilled water. Remove from heat and add coins/artifacts and allow to cool. Once cool, add all to plastic bowl and cover. Let rest for 5-7 days, then scrub with a tooth brush under running water. Return to liquid as neeeded and repeat.
Use sparingly.