Tin-plate
The thin iron plates for this purpose are usually made from the best charcoal-iron, the surface of which is made chemically clean by pickling in hot diluted hydrochloric acid. They are then washed and annealed in closed iron boxes, passed two or three times through the rolls to polish the surface and cause them to take less tin, again annealed and pickled, and subsequently washed with sand and running water, which leaves them clean and bright for tinning.
The plates are now put singly into a pot of melted grease, then into the tin-pot, containing the bath of molten tin, covered with grease; from this they are passed to another vessel with two compartments, called the washpot, in both of which compartments is melted tin also, well covered with grease, like the first. The tin in this pot is purer than that contained in the tin-pot. They are then lifted out of compartment No. 1, wiped with a long hempen brush on both sides, and again dipped--in compartment No. 2 this time, out of which it comes shining, to be at once transferred in an upright position to a pot of liquid grease, the temperature of which is maintained no higher than will keep the tin in contact with the oil in a liquid state, allowing the superfluous tin to run off, and spreading the remainder equally on the surface of the iron. See TIN; TINNING.