This blog was written by Chloe Thomson, a postgraduate student on Cardiff University’s MSc Care of Collections course.

Chloe worked collaboratively with Sejal Goel, a postgraduate student on Durham University's MA Conservation of Archaeological and Museum Objects course. Both were based at and worked with the team at the Wiltshire & Swindon History Centre in Chippenham, which houses the Conservation and Museums Advisory Service (CMAS). Positive partnerships are very common in the museum profession. This project exemplifies the best of this approach and what can be achieved when truly working together.

We are grateful to Chloe, Sejal, the team at CMAS and Heather Perry, the Museum Development Officer for Wiltshire, for their contributions to a successful outcome.

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At the end of last year, a selection of medals was brought to our attention which had been incorrectly labelled and required specialist attention to remove them. Labels are used by museums to identify objects by their accession numbers, enabling collections to be efficient and organised. Whilst the vast collection was certainly identifiable, labels had been attached using adhesives directly onto the metal surfaces, making them difficult to remove and potentially damaging to the material beneath. It was therefore decided by the Museum’s Collections Team that the labels should be removed by conservation students from Cardiff and Durham universities with the support of Wiltshire and Swindon History Centre.

Adhesive labels directly applied to the surface of the medals; the smooth surface on the copper stars were particularly difficult to remove the labels from and left a great deal of tarnish behind.

The process of removal was relatively simple; after an initial assessment using ultraviolet (UV) lights and observing the type of labels used, it was decided that acetone would be the most effective way to remove the label with the aid of swabs, toothpicks, and tweezers. This process is outlined below:

1. Assessment:

A UV light was used to identify any coatings on the medals which could react with chemicals introduced to the surface or require a stronger chemical to remove the adhesive label. Under UV, coatings auto-fluoresce (emit a colour) whilst bare metal does not. Luckily, only one medal showed signs of fluorescence and after consultation with the Senior Conservator at the History Centre it was decided this was adhesive residue due to the fluorescence being directly around the label. Hence work began using the acetone and original method.

These images show the medals under a UV light, nearly all the medals emitted no colours and it was concluded were not coated. Medal number 2006.4723 did have a coating of some kind around its label, demonstrated by the light colour emitted under UV, this was assumed to be an adhesive coating due to its position and thus unproblematic in the removal of the label.

2. Removal:

The first labels removed were done so with a great deal of caution; small amounts of acetone were used to wet the swab and then rolled across the surface of the label; a toothpick was then used to pry the label from the surface with tweezers used to gently lift it from the metal surface. Once the label was removed, the surface was swabbed with acetone once more to remove all residue and leave the medal clean. This was all done underneath a microscope to prevent surface damage such as scratching during the project.

However, for some medals the labels had left tarnish on the metal which not only affected the aesthetic look of the medal but impeded the respect shown to the medal and the service person who received it. We consulted with REME Museum’s Curator and staff at the History Centre on how to approach this matter, and it was decided where tarnishing was especially bad the metal should be polished to match the front of the medal.

The removal process in action.

3. Polishing:

Where polishing was necessary, three methods were conceived of with varying levels of abrasiveness. The least abrasive method was used first due to the risk of removing a layer of the base material as well as the tarnishing, with the more abrasive and introduction of chemicals being saved as a last resort. These approaches were as follows:

1. Goddard's Silver Cloth – a cotton cloth with a cleaning, polishing and anti-tarnish agent within the fibres used to polish many metals both within and outside of the conservation profession. This method worked for some of the medals, especially when coupled with acetone and in certain cases, the stronger solution of IDA (Methylated Spirit)
2. Eraser – a standard eraser is often used by conservators to remove surface dirt and tarnish from many materials. This was identified as being a step between the least and most abrasive methods brainstormed, however proved ineffective when tested on the tarnished medals.
3. Prelim – a paste used to clean metals which is spread across the surface of the medal and left until dried, when removed it leaves the medal clear of any tarnish. This was only used in the worst cases of tarnish as it is more abrasive than the Goddard’s Silver Cloth. If this had failed, the use of IDA and precipitated chalk was discussed which would have been even more abrasive, however prelim was successful when used.

This image shows the extent of the tarnishing on some of the medals from which labels were removed – this was one of the worst cases we found and required the use of Goddard's Silver Cloth and Prelim to remove most of the tarnish.

In total, we removed the labels from over 60 medals and polished a significant proportion of these. The project was rewarding due to the significance of these objects both to the Museum and the REME Corps, as well as providing the Museum with a method of removing labels in the future if needed. However, it is hoped that going forward the Museum will not find itself in another 'sticky situation' like this!