Workshop 1 The Cleaning of Silver Objects With a Basic Solution of Sodium Glycinate

Saturday, September 3

Max. 20 participants

Duration: 9:00 – 17:00 (includes transportation time)

Price: 125 €

Location: Finnish Heritage Agency’s Collections and Conservation Centre

Included in the price: transportation from and to Helsinki Senate Square (Senaatintori), lunch and afternoon coffee/tea


This workshop aims to study the use of basic sodium glycinate solution for cleaning tarnished silver objects. Sodium glycinate is currently proposed as one of the existing alternatives for the chemical cleaning of silver. It is a non-toxic and low-cost compound. It is also water soluble. This compound still shows a good selective reactivity to silver corrosion products (tarnish), being less reactive to metallic silver and its alloys.

This workshop will theoretically address:

  • Tarnishing processes of silver objects;
  • Most common methods of cleaning tarnished silver;
  • Chemical cleaning of tarnished silver with sodium glycinate: principles of the chemical action of the solution, reactivity of glycinate with silver and its alloys, efficiency and considerations in its use in conservation procedures;

The practical part of the workshop will cover:

  • Preparation of the basic solution (pH = 10) of sodium glycinate;
  • Cleaning silver objects in different tarnished states using appropriate procedures for each situation;
  • Evaluation of performed cleaning and guidelines on procedures.


João Cura D’Ars de Figueiredo Jr., Universidade Federal de Minas Gerais
João Cura D’Ars de Figueiredo Jr.

João Cura D’Ars de Figueiredo Junior is a chemist and currently a professor at the Department of Fine Arts at the School of Fine Arts at the Universidade Federal de Minas Gerais (UFMG) in Brazil. During his graduation, he served as a scientific initiation grantee at the Laboratory of Conservation Sciences (LACICOR) of the Center for Conservation and Restoration of Mobile Cultural Assets (CECOR) of the School of Fine Arts at UFMG. He obtained his doctorate in Chemistry at UFMG in the field of Inorganic Chemistry studying bronze and coordination compounds used in its conservation such as AMT.

Currently, in interface with the Department of Chemistry at UFMG, he develops research with materials used in the conservation of works of art, with emphasis on those focused on metal objects. Among these are the use of amino acids as coordination compounds in the cleaning of silver objects and carboxylates for corrosion protective coatings on silver and bronze.

Relevant publications

de Figueiredo Junior, João Cura D’Ars; Asevedo Samara Santos; de Souzae Silva, Maria Luiza Seixas; Araujo, Andrezza Conde; Quites, Maria Regina Emery. 2021.The Cleaning of Silver Objects With a Basic Solution of Sodium Glycinate: A Study on Artificially and Naturally Tarnished Silver In STUDIES IN CONSERVATION. , v.66, 1-9

Junior, Joao Cura D’Ars de Figueiredo; Asevedo, Samara Santos; Barbosa, João Henrique Ribeiro. 2014. Removal of Brouwnish-Black Tarnish on Silver-Copper Alloy Objects with Sodium Glycinate. In Applied Surface Science. v.317, 67-72

Workshop 2 Oxygen Consumption

Sunday, September 4

Max. 20 participants

Duration: 9:00 – 17:00 (includes transportation time)

Price: 125 €

Location: Finnish Heritage Agency’s Collections and Conservation Centre

Included in the price: transportation from and to Helsinki Senate Square (Senaatintori), lunch and afternoon coffee/tea


Join our experienced researchers in a workshop offering the theory and practice of oxygen consumption methods for the assessment of metal corrosion. This session will introduce you to the uses of oxygen consumption within the heritage sector. Through practical demonstration, we will explore the equipment and its application, methods of encapsulting objects, the measurement of individual artefact stability, management of anoxic storage and common pitfalls. We will examine data collection and processing using worked examples. A question and answer session will address your queries about refining the method for your research or management contexts.

We would encourage you to send details of your proposed application of oxygen consumption in advance to enable us to offer the best possible advice.


Nicola Emmerson and David Watkinson, University of Cardiff, Henning Matthiesen, The National Museum of Denmark, David Thickett, English Heritage

Nicola Emmerson and David Watkinson (Cardiff University)

David has taught conservation at Cardiff University for over four decades and Nicola studied in Cardiff and joined the teaching team in 2014. Within our Metals Research Group, we use oxygen consumption to record reaction rates of corrosion mechanisms and archaeological objects in controlled humidity. Our oxygen consumption data identified how rising relative humidity increases oxidation rates of iron and enabled us to develop guidance for managing risk to objects at the SS Great Britain, Museum of London and Mary Rose Trust, amongst others.

Relevant publications

Emmerson, N., Seifert, J. and Watkinson, D. 2021. Refining the use of oxygen consumption as a proxy corrosion rate measure for archaeological and historic iron. European Physical Journal Plus 136 (546). (10.1140/epjp/s13360-021-01478-w)

Watkinson, D., Rimmer, M. and Emmerson, N. 2019. The Influence of relative humidity and intrinsic chloride on post-excavation corrosion rates of archaeological wrought iron. Studies in Conservation 64 (8), pp. 456-471. (10.1080/00393630.2018.1565006)

Emmerson, N., Watkinson, D. and Thunberg, J. 2019. Flame cleaning of historic wrought iron: practitioner methods and their impact on oxide morphologies and post-treatment corrosion rates. In Chemello and Brambilla (Eds). Metal 2019: Proceedings of the Interim Meeting of the ICOM-CC Metals Working Group, 2-6 September 2019, Neuchatel, Switzerland. pp. 281-288. (

Watkinson, D., Emmerson, N. and Seifert, J. 2017. Matching display relative humidity to corrosion rate: Quantitative evidence for marine cast iron cannon balls. In: Menon (Ed.) Metal 2016: Proceedings of the Interim Meeting of the ICOM-CC Metals Working Group September 26-30, 2016 New Delhi, India. pp. 195-202. (

Watkinson, D. and Emmerson, N. 2017. The impact of aqueous washing on the ability of βFeOOH to corrode iron. Environmental Science and Pollution Research 24, pp. 2138-2149. (10.1007/s11356-016-6749-3)

Watkinson, D. and Rimmer, M. 2014. Quantifying effectiveness of chloride desalination treatments for archaeological iron using oxygen measurement. Presented at: Metal 2013 Edinburgh, Scotland. Interim meeting of the international Council of Museums Committee for Conservation Metal Working Group, Edinburgh, UK, 16-20 September 2013 Presented at Hyslop, E. et al. eds. Metal 2013: Interim Meeting of the ICOM-CC Metal Working Group, Conference Proceedings, 16-20 September 2013, Edinburgh, Scotland. Edinburgh: Historic Scotland pp. 95-102. (

Henning Matthiesen (Senior Researcher, National Museum of Denmark)

Henning Matthiesen (Senior Researcher, National Museum of Denmark)
Henning Matthiesen

Educated as a chemist, I have 21 years of experience working as a researcher at the National Museum of Denmark focusing on environmental monitoring and preservation of cultural heritage, with special emphasis on the in situ preservation of archaeological sites. I also research into the development of new, non-destructive methods for monitoring and quantification of real time decay of cultural heritage objects under varying climate conditions. I have used oxygen consumption measurements intensively for the last 15 years for quantifying decay rates of both metals, wood, bone, and various organic materials.

Relevant publications

Matthiesen, H. 2007. A novel method to determine oxidation rates of heritage materials in vitro and in situ. Studies in Conservation, 52, 271-280.

Shashoua, Y. & Matthiesen, H. 2010. Protection of iron and steel in large, outdoors industrial heritage objects. Corrosion Engineering, Science and Technology, 45, (5) 357-361.

Matthiesen, H. & Wonsyld, K. 2010. In situ measurement of oxygen consumption to estimate corrosion rates. Corrosion Engineering, Science and Technology, 45, (5) 350-356.

Matthiesen, H. & Mortensen, M. N. 2011, “Oxygen measurements in conserved archaeological wood,” In Proceedings from the 11th ICOM-CC conference on Waterlogged Organic Archaeological Materials, Greenville, May 2010, K. Strætkvern & E. Williams, eds., USA: International Council of Museums, pp. 123-135.

Matthiesen, H. 2013, “Oxygen monitoring in the corrosion and preservation of metallic heritage artefacts,” In Corrosion and conservation of cultural heritage artefacts, P. Dillmann et al., eds., Woodhead Publishing Limited, pp. 368-391.

Matthiesen, H. & Stemann-Petersen, K. 2013, A fast and non-destructive method to document and quantify the efficiency of metals conservation, In Proceedings from the ICOM-CC Metal conference, Edinburgh 16th-20th September, pp. 179-184.

David Thickett (Senior Conservation Scientist, English Heritage)

Henning Matthiesen (Senior Researcher, National Museum of Denmark)
David Thickett

Following a degree in natural sciences and two years of experience in industrial ceramics research, I joined the British Museum in 1990 with a specialism in preventive conservation and inorganic materials conservation research. Moving to English Heritage in 2003 as senior conservation scientist, I mainly research preventive conservation, and gained my PhD in archaeological conservation and chemistry in 2012. My recent projects have focused on historic house environments, acoustic emission, collections demography and epidemiology, non destructive testing, microclimate frames and optical coherence tomography.

I have used oxygen measurements to determine metal corrosion rates for over 20 years, initially with gas sampling meters and then three generations of non invasive meters based on fluorescence quenching. I have used the method extensively for testing archaeological iron and copper alloy artefacts proposed for display at English Heritage to reduce resources, improve sustainability and allow display in showcases with vulnerable organic materials. It has also proved useful for determining air exchange rates of print, photograph and painting frames.

Relevant publications

D. Thickett, Art08, Determining the Stability and Durability of Archaeological Materials, Jerusalem, 2008

D. Thickett, Presentation in original contexts via microclimates, Pre-prints of Preservation and Access, International Institute for Conservation, 2008, 98-103

D. Thickett, L. Csefalvayova and M. Strlic, Smart conservation: targeting controlled environments to improve sustainability in Pre-prints of 16th Triennial meeting of ICOM-CC, Lisbon, 2011, 19-23

D. Thickett and M. Odlyha, The formation and transformation of akaganeite, in Pre-prints of Metal 2013, 2013, 103-109

D. Thickett, Critical Relative Humidity Levels and Carbonyl Pollution Concentrations for Archaeological Copper Alloys in Pre-prints of Metal 2016, 2016, 180-187

D.Thickett, Oxygen Depletion Testing of Metals, Heritage 2021, 4(3), 2377-2389;