To clarify Butter: Put the butter into a saucepan, heat it slowly, removing the scum as it rises, and when quite clear, pour it carefully into clean and dry jars, leaving the sediment behind.
To de-salt Butter: Put into a bowl and pour over boiling water. Leave until cold. The butter will then have risen to the top of the water and can be lifted off. The water will have washed out the salt.