thermometer or use a spray of distilled water. Organic residues or particularly resistant deposits should be removed by
chemical means. Mechanical cleaning of the bulb should be resorted to only in extreme cases, but bear in mind that
abrasion can lead to irreparable damage. If cleaning does not fully re-establish the effica-cy of the electrode, it may be that
the electrode has aged. Ageing will show itself in the for of either a measure-ment error or a slow response.
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