The majority of the studied artworks were altarpieces, sculptures and/or wood-based works from different periods. Non-traditional gilding techniques have been first described in this paper, such as those that employ materials as oil in the gilding on bole, glue and bole with lead white in mordant gilding, vermilion in the preparation layers; and brass gilding or those with aluminium, lead chromate, mica or corla trying to imitate the golden hue in restoration or repaint processes. For the determination of the composition of the different gilded layers, spectroscopic techniques, such as FTIR and micro-Raman, and SEM-EDX elemental chemical analyses were successfully used.