פירוש על שבת 45:5

To mix: I found in the responsa of the Geonim, that we smoke a glass vessel with the smoke of olive oil until it blackens. And one [then] rubs off the blackness and puts a little oil into it, mixes it, dries it in the sun and [then] rubs it into the ink.

To smoke: This is also as I [just] explained.

Sap: Gome.

Balsam: Prunelier of the forests; like that which we make from sap.