A layer of dark oxide will form easily on a pewter surface as a result of chemical pollutants in the atmosphere, especially in our cities. Both public and private collectors have sought to prevent such oxidization by covering the freshly cleaned surface with a thin film of transparent lacquer, but they have found that a nylon-based lacquer affects the substance of an object; it is therefore not to be recommended. A more advisable, if more laborious, way is to clean pewter from time to time.

Cleaning pewter is not to be confused with polishing it. It is true that a hard, bright shine can be achieved by the rotating action of electric polishing wheels passed rapidly over a pewter surface, but such a shine is not consistent with the material nor with the craftsman’s original intentions.

Antique Collection

Pieces that do not carry relief work can be cleaned using horsetail (equisetum) and suds (or grain tin).

A process still to be recommended today for flat surfaces. Pewter with a high lead-content can be cleaned by immersion in dilute hydrochloric acid; this must be done with extreme care, since this dangerous liquid can cause substantial damage to object and collector.

Relief pewter should only be treated with plain soap suds or with a very soft brush. Dirt that has lodged in hollows, recesses, and other awkward places can be taken off with a varnish-remover, as can any traces of nicotine. It should be applied to a section of the object at a time and then rubbed off with a cloth.

Where pewter has been poorly kept and the surface has become thin, corroded, porous, or patinated, special care is required when cleaning; in such cases this is probably best left to an experienced restorer.

In the cleaning process it is important that the natural patina of the pewter remains unaffected. This patina gives the surface a grey or grey-black colouring, without being of any perceptible substance itself, like rust on iron or verdigris on brass. Thus it does not cause any substantive change to the object, but rather stains it, and in a manner which, far from detracting from its appearance, is much discussed and admired.

Repairs should also be entrusted to a proven expert; a restorer’s workshop is the best place for objects which have developed pores, cracks, or dents, and for objects which have been bent, cracks, or dents, and for objects which have been bent out of shape or whose handles or bases have come loose; here they can be filled, patched up, soldered, and made good.

Again, it is the professional restorer who should be left to treat `tin pest‘. The treatment is long and laborious, and success cannot be guaranteed in every case. The affected areas are scraped out and rubbed down, after which the object is boiled in a solution of water and hydrochloric acid. This is followed by an extended water bath to ensure that the acid has been rinsed off.

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Collections’ care and restoration of pewter