Answer by
LeheckaG (1826)
Paintings are restored primarily by cleaning contaminents off their surfaces,
and by repairing any canvas/fabric & frame damage.
Contaminents are painstakingly removed by rolling cotton-swabs over the painting surface,
human-saliva is often used as a safe-solvent.
Attempts are made to repair other damage using as orginal materials as possible,
and to only repair the damage without altering the artwork.