I say seventeenth-century; the following excerpt from William Salmon’s Polygraphice was published in 1701, but was plagiarised from Stalker & Parker’s earlier work, A Treatise on Japanning and Varnishing, published in 1668 (varnishing, varnish-making and finishing in general have long been popular topics amongst plagiarists).
I. To Varniſh Olive Wood Tables, Stands, Cabinets, Looking Glaſſes, Dreſſing Boxes, &c. Ruſh over the piece you intend to Varniſh, which being well done, ſet it by a ſoft and gentle Fire, that it may be well warmed, and ſo made fit to receive the Varniſh.
II. Then waſh it 10 or 12 times over with thick Seed lac Varniſh (which remained after the top or fine was poured off) with a Pencil [brush] fitted to the bigneſs of your Table, Cabinet, Frame, &c. letting it throughly dry between every waſhing.
III. If any Hillocks, Knobs or roughneſs does appear, when dry, then ruſh them off, at every turn as you meet with them ; and continue Ruſhing it, till it is very ſmooth.
IV. After all this, waſh it over again, ſix ſeveral times with the fineſt of the Seed lac Varniſh, and ſo let it ſtand three days, to dry throughly.
V. Then take Tripoli ſcraped with a Knife: and take a fine ſoft Rag, dip it in fair water, and then in the Tripoli, with which rub and poliſh it, till it acquires an admirable ſmoothneſs and gloſs.
VI. But you muſt be very careful, that you rub it not, nor wear away the Varniſh too much, for that is no ways to be repaired, but by freſh Varniſhing it again.
VII. After you have rubbed ſome conſiderable time with the Rag and Tripoli, you will do well to uſe the Rag often wetted without Tripoli, whereby you will obtain the better Gloſs.
VIII. Then Wipe off your Tripoli with a Spunge full of fair water ; and afterwards wipe off the water with a dry Rag : Rub it with Lamp-black and Oil all over, and wipe off that with a dry Cloth: and clear it with another.
IX. If after all this pains, your Work looks dull and heavy, and the Varniſhing miſty, (which is cauſed by poliſhing it before it was throughly dry, in moiſt, damp Weather) you muſt give it another ſlight Poliſh, and clear it up, as before, and that will give it its due Luſter.
X. If you have been too ſparing of your Varniſh, ſo that it is not thick enough to endure a through Poliſh, you muſt uſe again your fineſt Seed lac Varniſh, giving it 5 or 6 Waſhes more.
XI. And then, after 4 or 5 days time, in which it will be throughly dryed, you muſt Poliſh it, and clear it up, as before.
XII. If you deſire to keep the abſolute, true, natural and genuine color of the Wood, you muſt then only uſe the White Varniſh (in Cap. 4. Sect. I.) for that is the only thing which compleatly anſwers this end, for that being often waſhed with it, it neceſſarily heightens and increaſes the true natural Olive Color.
XIII. To Varniſh Wallnut Wood. The ſame Method is to be obſerved in this as in that of Olive, and the ſame Rules will hold exactly in all other ſorts of Wood which are cloſe and hard, and of a ſmooth Grain, as Box, Lime Tree, Pear Tree, Yew, &c.
Little has changed in over three hundred years.