This physical act should not be driven purely by aesthetic reasons. Cleaning of stone is critical for its well being. The cleaning process removes soluble salts damaging to stone and also allows us to examine the previously hidden signs of decay.

Before any cleaning can be carried out the cleaning methods and the level of clean need to be ascertained.

The main cleaning methods used by Adamson Conservation are;
  • Physical methods: these include brushing and rubbing, washing and steaming. David Adamson is an approved practitioner of the TORC, DOFF and Nd:YAG laser systems.
  • Chemical methods: applied as liquids or poultices, these may employ the use of alkaline treatments, acidic treatments or organic solvents, singly or in combination.
  • Special techniques may promote the use of impregnated sponge, ultrasonic equipment, heat lances, poultices or gels, and surfactants (degreasants or soaps).

Not all treatments are appropriate for all materials, and extreme care needs to be exercised when deciding which system to adopt. Due to the need to minimise the risk of damage, the 'do not clean option' should also be borne in mind.

Cleaning of Stone and Terracotta


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David Adamson is a PACR accredited conservator-restorer and is a member of Icon.