Glew

When the painting is originally on wood, it must be first detached from the ceiling or wainscot where it was fixed; and the surface of it covered with a linen cloth, cemented to it by means of glew[…]

Now Gold is easily associated to and with Copper; and so fit a cuspe, or point made of Gold to this Cupreous Iron; and with Borax and Golden Solidature or Soder (Gold Glew, which is made of Copper Money, a little Silver and Gold melted at the Eye is better) melt it after the accustomed manner, in a fitting Coal-fire, and then you shall have the Golden Nail so much spoken of.