A wide variety of non-ferrous metals were used in Viking Age Britain, including Pewter, Tin, Brass, Lead, Copper, Mercury and Bronze. Bronze and Brass have the same main component - Copper - however, the process of alloying Copper with Zinc to produce Brass, or Copper with Tin to form Bronze was rather hit and miss.
We cannot be sure that the bronze workers who handled these metals a 1000 years ago did or did not appreciate the various qualities that the alloys had. However, it is our habit to almost always underestimate our forebears abilities, and certainly the treatise on church metalwork by 'Theophilus' called 'On Divers Arts', suggests that they did indeed have an appreciation of the various metals that could be used. There is a certain amount of speculation as to the exact date of this work, written in northern Germany about 1100, but it compliments a more scant treatise written in the 8th century.
The clear distinction that we insist on today between Brass and Bronze did not exist in the Anglo-Saxon world, or if they did, they didn't worry too often about it. Processing often resulted in a metal referred to by Archaeologists as 'Copper Alloy' which safely falls between the two. The effect was to produce what can only be described as a 'Brassy Bronze' or even a 'Bronzy Brass'. There are only subtle differences in the working qualities of these two alloys, with Bronze being better at being forged, and brass having a longer working time prior to work hardening.
Wiglaf, would have had a broad range of metal working skills. But his speciality lay in non-ferrous work, i.e. casting. It's unlikely that he was itinerant, not that moving your workshop was impossible, just inconvenient. He would have had a workshop in Wichamstow, that was patronised by the local Thegn, which helped to keep him in business. From there, the workshops wares were exported or delivered to the people who commissioned the pieces.
The church and Minster of St.Werburgs also would have commissioned him to make various ecclesiastical bronze ware such as Thuribles, Censers etc; possibly even elements to shrines and reliquaries. More mundane items were buckles, sword fittings, casket mountings, horn mounts and stirrup mounts, once formally identified as book mounts. Sheet pressings or foils could also be made from cast dyes called Matrices and Patrices (the opposite of each other). Depending upon the volume of work, Wiglaf would have employed the skills of his wife, sons and daughters, and ultimately apprentices from the town.
The basic elements for the production of bronze and brass, were in all likelihood bought in by Wiglaf. That's to say that he didn't smelt the ores of copper, tin and zinc at the workshops. The simple reason for this is that these ores weren't all conveniently excavated from quarries on his doorstep. In fact, these metals came from a very dispersed source. Tin from Cornwall, Copper from North Wales and Lead from Somerset. These were not the only sources, and in fact a great deal may have come from abroad through a middle man to Wiglaf. Smelting itself is a filthy and risky job, not one that could be practised in a town, as your neighbours would have had strong opinions on the subject.
Although it sounds a barbaric practice, old bronzes were probably broken up and re-cast as new objects. Indeed, even Bronze Age work may have been located and unceremoniously melted down.