I heard recently about an old custom of making åfok, the slaked lime that is added to pugua' (betel nut) and pupulu (pepper leaf), from hima, the giant clam shell.
Like the limestone obtained from coral rock, the hima is baked in a hotno (oven) to a high degree. When it is fully baked and cools, one just has to touch it and the shell falls apart like powder.
But you still had to sift (ma kula) the powder in a kolladot (wire strainer) to remove dirt, grass and other impurities. Then you had åfok. You added water, according to one's taste, to make it a paste if you wanted. I was told that åfok hima was rather strong.
(apog or apug in various Philippine languages)