Wood is a living material, sensitive to all environmental changes: humidity, light, heat and parasites affect the inner structure of a wooden piece. To control the factors that affect the wood structure is what must be done when a wooden piece is treated to be conserved or preserved. To increase or reduce the humidity of a wooden piece, to kill the parasites from the outside using spray or steam, or by injection, or submersion and reinforce the internal structure are some of the techniques used in wood conservation, whether being sculptures or furniture.

Restoration, on the other hand, takes care of the external parts. Missing parts are replaced, cleaning or glazing is done if the piece requires it. Everything is done to restore the original beauty of the piece.

If a sculpture is incomplete, the restoration will supply the missing parts.

When wooden sculptures are covered with oil paint, or gold or silver engraving is called estofado (quilted.)

The technique consists of covering a surface with very thin leaves of the metal and then painting on it a specific design like flowers. Eventually, part of the painting is removed. The original surface can be flat, bas relief, or 3 dimensional. The quilted, or metal covering, allows for very rich and brilliant transparencies of the layers of oil painting. This technique has always been widely used for icon painting, and religious and decorative motifs.

To be able to restore a piece, if it has lost part of this quilt.  First, the weak parts, that is, unions or the thinnest areas, should be reinforced, Later the pieces should be isolated to be disinfected as a precaution against parasites. The next procedure is done in a traditional way. Using calcium carbonate as a base, gilding the metal and after the oil painting. Finally, the oil paint is grooved, to let the metal be visible, and therefore, highlight the original design.