Summary

Identify the type of metal before attempting any cleaning.
Only consider removing a patina after ascertaining that the surface of the object is not as originally intended and that the patina is not providing protection against further corrosion.
Wear gloves when handling highly polished artefacts.
Keep relative humidity below 45 % for most metals in good condition and below 35 % for iron and metals showing signs of corrosion.
Observe maximum light levels of 300 lux for metal objects and lower levels as appropriate for composite objects with light sensitive components.
Where possible, store metals in enamelled or powder-coated metal cupboards or acid-free boxes.
Do not carry out any treatment if unsure. Contact a conservator for advice.
Contact a conservator for advice regarding the treatment of composite objects.