Chemical treatments

  • BTA treatment – Benzotriazole treatment of a bronze age axe under vacuum (3% in IMS).
  • Tannic acid – Passivation of remaining iron in a Saxon shield boss, using tannic acid (5%).
  • Formic acid – Removal of copper corrosion on marine excavated silver coins, using formic acid (10%).
  • Chelation – Iron corrosion removal on an Indonesian dagger, using Disodium EDTA (10% pH6). Chelation tests using methyl cellulose gels with  varying viscosities and pH values on brass.
  • Desalination – Marine excavated signal cannons desalinated using sodium sesquicarbonate (5%).
  • Patination – tests on copper tokens using hot and cold patination techniques.


  • Thorough research and relevant testing prior to treatment.
  • Close monitoring and accurate note taking.
  • Health and safety in the workplace.
  • Adapting the treatment according to results.