- Documentation and research are basic principles. Every restoration must master the importance of the instrument.
- Conservation first. Original material will be preserved as far as possible, damaging influence shall be minimized.
- A detailed plan with goals to achieve is settled with the owner before any treatment.
- Reversibility is striven for. If possible, glues and solvents will be used according to the original.
- In any case of doubt, other professionals will be consulted.