I used 5% acidic vinegar. (White distillers pickling vinegar)
It does a good job loosening up the barnacles and softening up the "crust", then I scraped them off with a spoon.

Some of the shells dried a bit chalky looking but it easily wiped off.

Basically the shell proper is made of calcium carbonate and layers of protein.

The acetic acid of vinegar will eventually eat the shell if you leave them to long enough. .

Barnacles are the Calcite form of Calcium carbonate where as the aragonite of the abalone shell even though it is Calcium carbonate, is a different form. Also I think the protein layers in the aragonite seem to slow the penetration of the vinegar so that it is eaten slower than the calcite from the barnacles.

свернуть